How to Fix Outlook 2007 Cannot Send Email Problem with Windows Vista & Linksys Router

Outlook 2007 cannot send emails out There have been quite a few complaints that Outlook 2007 (running in Windows Vista) is not sending out emails properly when paired with certain Linksys routers. I actually experienced this recently – what a mess. Thought I would share a quick fix and save some of you from hours of hair pulling.

For one reason or another, my Linksys WRT54GL wireless-G router began intermittently dropping DNS connections ( even though the default gateway ( respond normally to pings. In short, I can see and access other computers in the local area network, but there is no internet connection. After 2 weeks of tech support calls and more than 4 hours of total support time, the effort finally paid off. Linksys is sending a replacement unit.

During each call, tech support suggested changing MTU settings, disabling Block Anonymous Internet Requests, hard resetting the router, re-flashing the firmware, power cycling the modem & router, running static IP & DNS settings on each computer, adjusting various wireless settings, etc…. You name it, we tried it. Of course, after each tedious call, the router would work fine. After some usage, the DNS drop would return. It got to the point that every 24 hours, the router needed a hard reset and a full re-setup to work properly again.

The WRT54GL has a 3 year warranty so I chose the cross shipment method for replacement. Cross shipment is where Linksys sends you a replacement unit first. After you receive the replacement, you simply send back the defective unit as opposed to having to send in your unit first before Linksys sends you another. The only difference is when you choose the cross shipment method, Linksys will put a hold on your credit card for the retail amount of the unit that they have sent you. Once they receive the defective unit, the credit card hold will be cancelled. Fair enough. I went through the RMA process and am awaiting a replacement unit.

After dusting off and setting up my old Linksys wireless-B BEFW11S4 router, all was well again… except for Outlook not being able to send out any emails! After some quick research, it turns out that the BEFW11S4 has been well documented to have email send issues. Two must do’s for this router to unblock Outlook sending emails are:

  1. Set Max MTU to 1492 (rather than the disabled default of 1500)
  2. Port triggering should be setup with these settings
    • TriggerPort Range: 25 ~ 25
    • IncomingPort Range: 113 ~ 113

After these settings, both Outlook 2003 (running under Windows XP) & Outlook 2007 (running under Windows Vista) were still not able to send emails out. I had to further tweak each computer manually to send out emails via Outlook. Here is what I had to do in the time being until the new replacement router arrives.

Under each Outlook email account, I removed my normal SMTP setting of (your SMTP will be different and is based on your own domain name). It was replaced with an SMTP setting from my ISP – in this case, my cable provider. This solved the XP system but not the Vista system. For Outlook 2007 under Windows Vista, when using your ISP’s SMTP, an additional step of disabling authentication is required.

Under Tools >> Account Settings >> Account (Double clicking on each email account) >> More Settings >> Outgoing Server Tab, uncheck “My outgoing server (SMTP) requires authentication” like so:

Outlook 2007 SMTP authentication

Voila! Emails are going out again.

Funny enough, after switching SMTP settings, I disabled the above Max MTU settings and Port Triggering on the BEFW11S4 router and emails are still going out. Go figure!

Not sure why there are so many issues (& resolutions) in the Linksys forums regarding email send issues with certain Linksys routers but there you go. Hope this quick fix can help others with your Outlook email send problems.

In the meantime, I hope Purolator gets here quick with that replacement unit! I miss my faster wireless transfer speeds and stronger WPA encryption!

Ian Lee
Work from home dad, marketer and photographer. Fallen in love with basketball all over again as I coach my daughter's team.

149 thoughts on “How to Fix Outlook 2007 Cannot Send Email Problem with Windows Vista & Linksys Router”

  1. Hey thanks for stopping by my site, i noticed through my recent readers on MyBlogLog.

    Awsome post too bad I don’t have Office 2007 yet, i’m sure ill get it with my new computer before school starts in september.

    I hope you find my content good enough to subscribe to my feed, i have already subscribed to yours!

  2. THANK YOU THANK YOU THANK YOU!!! My provider didn’t even know how to fix this but he lead me to google and to look up this problem….I looked at my outgoing server settings and unchecked that box you said and wow… my e-mails are now going out!!! THANKS for your help!! Paula

  3. Thank you!!! I second Paula’s comment. I got this new fancy XPS M2010 with Vista and just could get email to sent for the past few weeks. Compared everything line by line with my old machine and almost pulled my hairs out 😛 Glad I was able to google your tips.

  4. You are a genius! Thank you – for the first time in 4 months I can send my personal mail from Outlook 2007 without switching to that horrid winmail. Thank you

  5. @Margaret: You are welcome. Sorry to hear that you were not able to use Outlook 2007 for the past 4 months. But also glad to hear that things are fixed now. Do enjoy!

  6. We are having the problem with Outlook 2007 and turning off the authentification works for a while, but then later needs to be turned on, then later needs to be turned off again.

    No clue yet, our ISP who we use for outgoing mail does not see a problem because they only see the traffic that goes. I believe it is something in Outlook 2007, not at the ISP. If anyone has more information, please post.

  7. Also having the problem but with Outlook 2003 and turning off the authentification works for a while. 2 new noteboooks running fine on Vista and Outlook 2003. Only that 3 original pc cannot send out msg in outlook. Tried everything. Agree with Don Williams that its Outlook’s problem and not OS, Router or ISP or anything else. Will fiddle around the outward mail server port in outlook 2morow. Will update if it works.

  8. Ian, I still am unable to send emails after making your suggested tweeks for Outlook 2007 (Vista) using a Linksys router. Any other suggestions? I’m losing my mind!!!!

  9. @Meg: Many ISP’s are beginning to block port 25, the default smtp and this may be your issue as well. If you can provide the following info, hopefully we can help you troubleshoot the no-send issue.

    Operating System: Vista
    Email Client: Outlook 2007
    Linksys Router (model):
    Email Address (everything after the @ sign):
    SMTP Setting:
    SMTP Port (See Advanced tab from above image):
    ISP (the provider that you use to surf the internet):

    Let’s start from there.

  10. Similar problems to Don, NOS and Meg. E-mail works one day and not the next. Brand new Dell E1705 with Vista, Outlook 2007, linksys befw11s4 v.2,, has been working with the box checked for outgoing requiring authentication,SMTP port = 25, Verizon is ISP.

  11. Eric, what is your SMTP setting & who is your ISP?

    Operating System: Vista
    Email Client: Outlook 2007
    Linksys Router (model): befw11s4 v.2
    Email Address (everything after the @ sign):
    SMTP Setting:
    SMTP Port (See Advanced tab from above image): 25
    ISP (the provider that you use to surf the internet):

  12. Ian,

    SMTP setting: Use same setting as incoming server
    Verizon DSL is my internet provider, my web browser is MS explorer.

    BTW – I can’t send or receive e-mails when my email issues pop-up.

  13. Hey Eric,

    It sure is odd that both receive and send breaks. This tells me that either or both SMTP and POP settings are off. Your SMTP should not be the same as your POP setting. At least not per Verizon’s instructions.

    Try the above settings and see if you can at least receive email. That would be step 1.

    I have had my own intermittent send issues with the BEFW11S4. This particular router has been well documented in the Linksys forum to have major issues with sending emails in various setups.

    Have you tried Verizon tech support? They should be able to help since you are accessing their emails.

    If you have tried the above settings (including the Max MTU & port triggering), I would recommend a different router. In my opinion, I think the BEFW11S4, although it works, is out dated and does not work well with more recent setups.

    If you find a solution do post back. The only way I was able to resolve intermittent issues on the BEFW11S4 was to switch back to a newer WRT54GL.

    Hope that helps.

    Addon: Forgot to mention that you can try by-passing the BEFW11S4 temporarily by plugging your computer directly into the modem. If sending and receiving email works this way, then you know the router is the culprit.

  14. I have found an issue with server address’s, both my incoming an outgoing mail servers are the same address and every now and again it stops sending mails and just keeps asking for login details for the outgoing mail server. I found whenever this happens if i check the account setup it has changed the outgoing mail server to localhost. Change it back to the SMTP server address and it works again.

    Looks like a bug in Outlook to me, very annoying.

  15. Hi –

    I’ve got a “can’t send email from Outlook/Vista with a Linksys router” problem

    Operating System: Vista
    Email Client: Outlook 2002
    Linksys Router (model): WRT350N-SG Wireless-N Gigabit Router with Storage Link
    Email Address (everything after the @ sign):
    SMTP Setting:
    SMTP Port: 465 (att uses SMTP:465 and POP3:995

    I can receive mail on this Vista PC (and all other PCs (non-Vista) can send/receive). I cannot SEND mail on this Vista machine.

    In Outlook under “Test Account Settings” – all Succeed except last step which fails stating “Unable to send test Message. Please verify E-mail Address field.”….Ok, I re-entered/confirmed correct address, tried other accounts and deleted the outlook account to try and fix, to no avail.

    I tried 1492 and 1450 MTUs and have tried port trigger ranges inclusive of above SMTP/POP3 for === Seems like my email account name is getting truncated?

    Spoke with Linksys and – both collude to blame Microsoft ;-)…please help me.


  16. Ted, since your email is at and your ISP is at, you could be affected by RR blocking port 25.

    Have you tried accessing the affected account on your non-Vista machines? Does this work?

    I would also try plugging your problematic Vista machine directly into the modem (by-passing the router) to see if the router is the cause.

    Hope that helps.

  17. Ian, thank you for your comments. uses 465, not 25 (25 doesn’t work with if you’re accessing them via another ISP). 465 works on other machines (non-Vista PCs). So RR blocking 25 isn’t problem. I don’t have another router to access my RR connection and so can’t bypass it either (it’s a cable BB connection). ?

  18. Ian, sorry, your other question, yes the account works if I go to it either as web mail access or via an Outlook Client on and XP machine (on the same network). Ted

  19. Ted, glad to know you have the port issues sorted. This sure sounds like Vista is the culprit.

    From your Vista machine, instead of plugging the network cable into your router, can you plug it directly into your cable modem? You will have to unplug your router from your modem before doing do. Then reboot and try again.

    Not sure if your hardware will allow you to do this but if you can, it will at least remove Linksys from the equation (or some combination of Vista + Linksys).

  20. I’ve been having intermittant problems with e-mail getting stuck in Outbox. Just read a response in MS forum TechNet where someone said hand type in e-mail address. Tried it and it worked. Seems some e-mail addresses when inserted from Contacts puts parantheses around e-mail addresses. These will be the “intermittant” ones stuck in Outbox. Hope this helps someone.

  21. I am not able to send any emails. I am not able to send any emails using outlook express or yahoo. It gives me an error message.

  22. I am using Outlook 2007 on Windows Vista Business and cannot send mail. I am also using Windows Mail (OE with a new name) and having absolutely no problem sending mail with that on multiple accounts. These OE accounts that work fine are on my domains hosted by the same ISP as my Outlook 2007 email, which does not work.

    I am connected at home via Netgear Wireless router to my Verizon DSL service. I have tried many, many things (smtp auth on/off, port 25 changes, etc) but nothing has resolved the issue… until now.

    I tried Lou’s solution above and it worked. Bam! Messages are gone. Note that all of my contacts were loaded in using a PDA running PocketPC and using Microsoft Hotsync. Any contacts that I had manually loaded in were working fine. I just never made the connection that the imported contacts could be the problem.

    I opened the imported contact for an email that was stuck in the outbox, re-keyed the email field and saved the contact, re-addressed the message to the same guy and it sent immediately.

    Might be a fix for some of you, especially if you imported contacts to Outlook 2007.


  23. The root problem is that ISP’s (such as BT, wanadoo/orange …) only allow sending email via their SMTP server. The default port for SMTP is 25 (i think). They block this port and force it to go via their server only. Therefore you need to switch your outgoing smtp server to be the one the your ISP provides.
    Alternatively you may have an alternative SMTP server as long as its not on port 25.
    They do this to stop spam senders.

  24. Update on my earlier post. I have tried a simpler approach. Any messages that get stuck in my Outbox are always ones that are addressed to an Outlook contact. When a message gets stuck, I open the message, and double click the name in the TO: field to open the contact. I then just “SAVE & CLOSE” the contact without making any changes. I hit SEND on the message and it goes… Every Time.

    Future messages to that contact are not held up, but get sent immediately. In my humble situation, this is definitely something to do with importing contacts.

    (Do I get a free t-shirt or something for discovering this…?)


  25. Hey – update on my earlier post on outbox messages stuck. I was using Office 2003 (and OE 2003), after many patches, and yes the earlier posts on fixing imported addresses from contacts worked, yet still have intermittent stuck msg complaints from a persistent and tireless user community (my wife). “My” solution to all issues was to break down and buy Outlook 2007 (only) for $109. Installed fine, everything works perfectly now (relative term for MS). Not sure that all noted that my original query was about OE 2003, not OE 2007. Thanks for the help along the way. This is what I get for trying to run XP Office on Vista OS.

  26. ok so i am not a computer person and i’ve tried to fix this problem myself but it obviously is not working. i have outlook 2007 with XP. I just upgraded to 2007 a few weeks ago and the email worked fine at first but then it stopped. i get error messages coming back undeliverable saying that my email was denied from that location or something along those lines. i don’t know how to fix this and am hoping that someone can give me easy to follow dummy proof instructions so i can fix this. 🙂 thanks

  27. Hello,
    Since I’ve had Vista, I have not been able to send email via Outlook 2007 or 2003, as well as Windows Mail. I do not have a router anymore. I certainly can receive mail but just cannot send it. I have comcast cable for my hi-speed internet service, and, thus, I set my SMTP to and I keep the Authentication Required box unchecked.
    Any clues??
    Thanks, Diane

  28. I have problem using outlook 2003 or Mozilla sending out emails on my wired or wireless computers. Receiving is perfectly fine at anytime. My setting is as follows:

    Operating system: Window XP
    Mail Client: Outlook 2003 or Mozilla
    Router: Linksys WRT54GS Wireless G firmware V7
    Email addreass: [email protected]
    SMTP:, port 25 or 587, secure and authentication used

    If connected directly to cable modem, everything works fine. Just when plugged into the router, sending email is blocked with the error message “ blocked by idap:ou=rbl,dc=net” in both Outlook and Mozilla, meaning Outlook is not the problem as Comcast blamed. Amazingly, when I tapped into my neighbor’s unsecured wireless network, with Linksys router and Comcast as ISP, I am able to send and receive emails. But when he taps into my network, sending email is not working either. Seems like router problem, but I suspect Comcast may have contributed to this problem. I have contacted Comcast, Linksys and HP help, they all said it is not their problem. Oh, I went out to buy another D-link router and new Linsys cable modem, and I encounter the same old frustration. Please help.

  29. I noticed your blog and need to know who you use. I am having trouble with my blog and am trying to change. What you are doing here is what I am after. Please send a response. I am despirate.

  30. Vista + Outlook 2007 = doesn’t work sending emails. Went through the BS tech support changing ports to 995, 465, turning on SSL. Webmail works to two different POP3 accounts, but Outlook doesn’t. If I run Outlook 2007 as a normal user it fails. If I right click, run as Administrator, then I can Send emails. I don’t know what the difference is, or how to set it permanently. Thanks Microsoft.

  31. Not all IT literate so pretty peed off…I have a new Dell computer (XPSM1330)and it came with vista and a MS Office disk. I tried to set up outlook this morning to accept a work email address with same incoming and outgoing IP address (numerical not in words). This was to work alongside my home mac which uses an orange livebox (the home account works fine) but neither the mac (using the switch identities mode)nor the PC can send emails from my work account. I can receive mails but cannot send them. The bizarre thing is that I took the laptop to a IT repair shop this afternoon and it worked whilst I was there (!) but they have a BT line. Orange technical support was pretty useless but surely its them at fault otherwise why did it briefly work? Any advice? (settings are at 110 and 25 – having read loads of postings on various sites) Thanks all

  32. I have been unable to send messages from either my pop or IMPA email accounts since installing Outlook 2007 on my new XP Dell laptop. I have tried this with my dsl line, on my campus wireless, with tech folks, and everything I have tried, including in this post, is still leaving me in the dark. Since, I have been using mozilla thunderbird but would like to be able to use outlook again. Any ideas?

  33. hi
    i’m desperate need of assistance! bought new hp laptop today and need to set up outlook for my business. i have saved my emails as a pst file from my other pc onto a usb. i am now at a friends house – they are with bt, and i can’t seem to import the pst file to show all my emails.
    i’ve googled incoming and outgoing mail server to find that out – is the only thing i need to get from bt the username and password? my friend says she’s never had one, as she now uses michillinda for her internet connection. not sure if that affects it? i’m so stressed as can’t reply to brides for their weddings – i’m a wedding planner! aaaagggggggggghhhhhhh!

    thanks very much if you can help me. i’ve just been crying for at least 10 minutes! sore eyes now, so off to bed.

  34. I was having similar problems with my Outlook 2007 and Vista. I am also running Trend Micro. I was unable to send any e-mails over 2mb. However I had a brain wave and decided to shut down Trend Micro, suddenly I could send 3mb files. In the settings of Trend micro I have since disabled “Check for threats in Outgoing Mail” under “Virus and Controll” settings and now everything is working fine!!

    Also another point that might help for some people, disable all add-ins and see what happens.

    I hope this helps people as this is a very frustrating problem and took me quite some time to figure it out!


    As all those previous posters mentioned, i was unaware of this ATT change for SMTP delivery. as it apparently seems that i got this without warning when i started sending mail through my router and notice that even tho i could receive mail i couldn’t send it.. funny thing was as a tech I’ve always had 2 wireless transmission ports going to different providers and when i couldn’t send on one i would send on the other. that was until my router bridge died and had to switch over to the ATT circuitry.

    Woah! no more mail send??? as I’ve had this happen on other connections (usually public) and since i program routers, this seemed hairy, when i stumbled on Google to find people blaming Linksys for a problem they didn’t have especially since thats code i work with.. further examination found, as all you have spoken about for the last several months, is that the no-email play contributed to the router blame when there weren’t any, and the most likely culprit is ATT.

    I never had port 25 problems in the past: so it was good when I tried this solution as a workaround and it solved a temporary issue..


    first: if and when you change Outlook, mine was 2003, oh and I do have Windows, Mac and Ubuntu machines as i am totally agnostic to issues relating to bloat, crap, and humanware, the latter (stupid human policy implementations) relating to enterprise/politics/money and outsourced stupidity! (and these are all humanstupid) a machine doesn’t need a human to screw it up. (technoRANT closed)

    you will change the ports for workarounds: the SMTP port mapping on the last page of Outlook’s “email account settings”: “more settings/advanced” page please set that to SSL first close and go back into setting, change the port to 465 as my pop3 did seem to work just fine! save and exit BUT BEWARE! FOR THIS TO WORK! WHEN YOU HIT THE SEND MAIL BUTTON YOU BE ASKED TO ACCEPT A KEY(CERTIFICATE) IF YOU DON’T, YOU WILL HAVE REAL PROBLEMS, AS THIS KEY ALLOWS YOU TO TRANSIT YOUR MAIL THROUGH TO YOUR OTHER MAIL EXCHANGERS YOU HAVE ACCOUNTS FOR VIA ATT ONLY! and for this workaround and I’m referring to you war drivers out there that roam the autoconnectable public domain of open access points with your laptops. since this is a setting most commonly relateable to ATT this effect will not sit well for most other providers and connections that don’t have this problem. that you may have to change back for.

    solving the problem is definitely asking your ATT PROVIDER THROUGH THE FORM TO CHANGE THIS:

    In any case, AT&T allows port 25 connections to its own mailservers, and they will remove the port 25 block on your service if you request it. You can actually do this *online* without having to spend time on the phone… go to the following link for more information, and see item #4 on that page:

    You can have this lifted online at:

    Under “Abuse type” select “Opt Out port 25”
    Under “Abuse Occurred In” select “email”

    After 24 hours, power-cycle your modem to activate the change.

    last few lines lifted from previous posts that really solved some issues, thanks to Amir and Peter for those little nuggets

  36. I must congratulate and thank Bruce Sellnow (posts on Sep 1st and 11th)- he hit the nail on the head. Who would of thought that his simple fix would alleviate so much frustration. My own machine is running Vista Business and Outlook 2007 as was Bruces, and suffered the exact same fate. I confirm and reiterate, his solution is 100% successful for fixing the “outlook will not send” problem we were experiencing….and it is most assuredly an issue with importing contacts

  37. Hello all – very relieved to say all working now and for users in UK the problem (despite them refuting this and a pretty ineffective but undoubtedly expensive call to their help desk) was Orange not allowing non Orange email addresses to send mail over their broadband connections. Have moved to BT and it now works fine. Hooray – so not a problem with Vista working in conjunction with Outlook in my case.. thanks all – have a great 2008

  38. I just switched to a new computer with Vista and Outlook 2007. I could receive email through Outlook using my account, but I could not send email. I would keep getting an error message about needing to verify my email address. I saw the postings about unchecking the box requiring authentication for the SMTP server in the Outgoing Server tab of the Email Settings and decided to try that. However, when I got to that screen, I saw that the authentication box was not checked. I decided to check the box and see what happened. Now I can send emails just fine! I realize that this is contrary to others’ experiences, but thought I should throw it out there in case anyone else is in my situation.

  39. Outlook 2007 on XP and Vista, using I went thru some of the ideas above, SPA unchked, direct to DSL modem. Changed to to complement my POP3 and all is well. Need to talk to both vendor, cause Verizon DSL wants you to use their outgoing server???

  40. I have a laptop come with Window Vista+outlook2007 and I can’t send out email at work using wireless connection but when I go home using my local internet provider cable line then it work. So strange! I try to uncheck the outgoing SMTP box but still not work. Please please help me out here!

  41. I have a lapotop working with XP and 2007 outlook. I get the system undeliverable errors too often. Turn on shut down to remove the problem temporarily. I am running thru a belkin router but it has issues when ever i am out in the field. Anyone know how to fix this.

  42. I was having problems sending email using Outlook 2003 & 2007 after new router. Bypassing the router emails would be sent fine, thus router was the culprit. Changed MTU to 1492 and it started working. Thanks, Ian!

  43. Hello:

    I am in charge of about a dozen computers here. We just added three new ones with Vista Business and Office 2007. With one machine send and receive works but some emails don’t come in until the next day. Doesn’t seem to be a pattern of who sent it and whether there is an attachment or not. My second machine works fine. The third machine has a problem sending and receiving SOME emails. Some outgoing addresses bounce back and some just disappear. Some incoming messages come through and some disappear. We have a Linksys BEFSX41 router(no wireless). We also have Exchange. The IT staff for our server have spent hours to make sure there is no problem there. Thanks for any help you can give.

  44. Well, I had the same problem. Please goto Internet Email Settings -> More Settings -> Out Going Server Tab .. Here leave the Authentication checked and provide the login info again. see if it works. Cheers.

  45. Help! I am running XP SP2 and just upgraded to Office 2007. I have a wireless network, all linksys components, and comcast is my ISP. I have had NO problems whatsoever with outlook express. However, I can NOT send or recieve mail in outlook 2007. Is this just a security setting somewhere or something simple like that?

  46. Hi,

    Would someone be willing to help me? I’m experiencing the same thing as most of the other people on the message board have experienced. I have Windows Vista Premium and I’m unable to send emails from MS Outlook 2007. I have a linkys router, DSL service, and I’m trying to send emails from a verizon account. The SMTP is: I have unchecked the box, and I can’t get it to work. Help!


  47. I have done most everything everyones has suggested, none worked until the set the SMTP to match the POP account on the Outlook 2007 PC. So I have 2 XP PCs Outlook 2003 SMTP=; 1 XP PC Outlook 2007; 1 Vista PC Outlook 2007 Now all is happy. go figure!!

  48. Help!!

    I just discovered that some of the emails that are showing in my “sent” folder for Outlook 2007 were not actually received… it looks like this happens when I have a link in the body, although not sure why as it appears to be a recent problem (or one I never realized). I have links in my signature so not sure why this matters, but it’s the only thing I can see so far. This appears to be true if I reply or forward an email that had a link in the original message.

    any ideas?

  49. Hi Pete,

    I also have the same problem like you. The email that i sent is already in sent box, but people who suppose to receive my email is not receiving anything till now. I notice that this problem happening from certain date. Please help me….
    Is this has something to do with virus, bug??

    Thanks a lot for your help

  50. I have the same problem, however, I have two different routers, a Linksys WAG200g on ADSL and a SMC Barracade SMCWBR14-G on Satellite connection. The linksys fails, while the SMC passes and works..
    At first I thought it was the ISP, but then when I switch back and forth I see its working.

    my System is WinXP SP2, Office 2007.
    I treid the MTU < 1500 & auto but did not work..
    here is the Linksys workaround (it did not work)

  51. I am having problems with an email that is blocking my sending other emails. I attempted to forward and email and it keeps coming up – ” Message could not be displayed
    Windows Mail encountered an unexpected problem while displaying this message. Check your computer for low memory or low disk space and try again.” I cannot delete it due to another error message: “An unknown error has occurred”. Help! I purchased this computer last year with Vista on it and it has only given me problems ever since…

  52. Very handy tip for Vista users and this has been a definate issue with email on vista! thanks

  53. To disable the SSL Authentication is not a good Solution. Then you cancel your secure login. Try to use the cloce mac address feature on the linksys router. Some ISP require that, so you clone the mac of your PC to your Router. I had the same problem an than it works finde. Best regars from Hamburg in Germany…. Michael

  54. I have a simular problem. windows vista with outlook 2007 and trend micro with a linksys router but not wireless. heres my deal. i setup 100s of computers with outlook 2003 with no issues. i get this vista machine with outlook 2007 and it sends and receives fine but when you add an attachment over 500kb it just sits in the outbox. i tried webmail and it sends fine so i know its something to do with outlook 2007 or trend micro. i disabled trendmicro in services and tried again and no luck. i thought it was business contact manager so i removed that. still no luck. it cant be an smtp setting because no mail would go out then. it has to be something to do with trendmicro or now Im reading maybe linksys.

    any suggestions?

  55. I cannot send email anymore. Up until last week, I could receive and send email fine. I can not attribute any installation or system change to causing this error to happen.

    I am running the following:
    Operating System: MS Vista Home Premium
    Email Client: Outlook 2007 (12.0.6212.1000) SP1 MSO (12.0.6213.1000)
    Linksys Router (model): WRT54G
    Email Address
    SMTP Setting:
    SMTP Port: 25
    ISP : Road Runner – Time Warner Cable

    I keep getting the dialog box that tells me to enter my network password. I do (and check to save it) and then it won’t down load or send my email!

    Exasperation is an understatement as I don’t know what I am doing wrong and have spent over 25 hours reviewing help/MS KB articles/discussion groups/surfing the web for solutions and trying different things.

    I have tried the following:
    — I am able to view email on the road runner website, so I know that the
    email/password is correct.;en-us;290684
    executed method 1 and method 2;method 3 said not to use if you were
    running vista
    — Removed all accounts on both the admin user and the standard user,
    rebooted and added the account back to the standard user login again.
    — Turned off inbound, outbound, IM scanning, Spam filtering in McAfee
    — uninstalled McAfee
    — installed Eset Nod32
    — tried the port thing in the Linksys admin screens mentioned above.
    — tried the checking/unchecking mentioned above.
    — UnInstalled and re-installed Outlook 2007
    — reset the Linksys settings to factory settings and reset up Linksys settings
    — tested this email account and was able to receive email on an XP machine running Outlook on my network.
    — downloaded and ran System Mechanic and resolved all identified errors.
    — installed Zone Alarm

    My email still doesn’t work.
    Someone suggested that I uninstall and reinstall VISTA. I really don’t want to do this.

    Does anyone have any suggestions?
    Your help regarding this error would be MOST appreciated.
    Thank you so much for your time.

  56. Michael & Leila,

    1. Have you tried by-passing the Linksys router and see if this works?

    2.a. Or tried setting up your account on an XP machine but still have it go through the Linksys router and see if this works.

    2.a. Use the XP machine from 2.a. and by-pass the router and see if this works.

    With these steps, you might be 1 step closer in determining where the breakage happens. Not sure why Michael’s situation would break with 500+KB attachments. That is odd indeed.

    So far you know:

    Vista + Linksys = does not work

    Now fill in:

    Vista – Linksys =
    XP + Linksys =
    XP – Linksys =

  57. Help!

    I couldn’t send my emails from Outlook 2007 anymore. I m using OS-XP and Net gear router. As soon as I click the send button the email goes to out box folder and remains there for ever. But I m receiving some emails and that really worries me. Please help.

  58. Another follow-up from my earlier post last September – I’ve been monitoring this thread ever since. On my laptop, I’ve connected to several different routers at family and friends’ homes, be it Linksys, Netgear, D-Link and a couple others. Every time I have a message stuck, I’ve noticed that it’s addressed to a person in my Outlook contacts that I haven’t used in a long time, specifically one that I haven’t SENT anything to from this laptop since upgrading to Outlook 2007.

    FIX: Same process – open the email in the Outbox, double click on the recipient, which opens the contact card. Click Save and Close and then send the email… Still works every single time, regardless of the router. I just wanted to refresh this response to let you know it’s still a fix for me…

    Sidebar: I really just need to go through all my contacts and open them and save them. I’m sure this would solve the problem. I wish I wasn’t so lazy…


    – Bruce

  59. thank you very much.. my windows mail is working again after unchecking the authentication thing…. after almost 7 weeks of’re the only one who solved my problem. thanks again.

  60. Ian,

    Thanks for your suggestions.
    Since I last posted on Mar 8, I was able to prove the following:
    – Vista + direct connection to cable modem (without Linksys router) + Outlook 2007 = did NOT work
    – XP + LinkSys + Outlook 2007 = works
    – Vista + router at Panera coffee shop (couldn’t confirm router type – they didn’t know brand) + Outlook 2007 = did NOT work

    So I went for drastic measures! I backed up my data files and re-installed Vista Home Premium.

    I re-installed Outlook 2007 and moved my outlook data files in place.

    Outlook 2007 set up wizard would NOT set-up/find my Time Warner Cable (ex-Comcast) settings. After setting up the email account manually (using the settings that I had used before, including unchecking the auth box) and email still not working and then talking with 2 incompetent TWC help desk reps who gave me 5 pieces of totally incorrect information (one told me that I shouldn’t put in the network password) , I finally was able to get my account set up correctly after talking with a competent TWC rep, who told me to uncheck “my outgoing server requires auth”,

    Okay — are you sitting down?

    I finally HAVE EMAIL AGAIN!!!!!!

    I don’t know why the reset up of email didn’t work right away after the VISTA reinstall even though the settings that I manually set up were exactly the same as what I ended up with….

    And more importantly, I have no idea what in VISTA got corrupted to make Outlook 2007 email all of the sudden stop working. I am estatic to report that VISTA + OUTLOOK 2007 + LINKSYS is living and playing well together. I am just hoping that one of the pieces parts doesn’t all of the sudden grab his bat and ball and head for home leaving the others in the lurch to play the game alone!

  61. On the DOT !! This is very Helpful JUST UNCHECK THAT BOX.. Thanks for sharing this. Yahoo / MS should add this to their FAQ

  62. Hi



  63. Re: Linksys: Outlook Express still will not send email even though the “Authentication…” box is unchecked.

  64. I have a web hosting customer who reported the same problem trying to send mail out through my mailserver w/ Vista Home and Outlook 2007, and he said he googled and found a fix to be to disable “my outgoing server requires authentication,” yet I know my mailserver requires it. So it must be a bug in Outlook 2007 for Vista. He can send mail now. But if my mail servers were open I’d know about it.

  65. I have vista and a trial version of Outlook 2007. Everything worked fine until a week ago and now I cannot receive or send mail. the error messag reads:

    Task’my email-Receiving’ repored error 0x8004218: Outlook cannot connect to your incoming (POP3) email server.

    Any suggestions???

  66. Hi – I just had a similar problem with the same error message, but the solution was different. The problem was that I had copied and pasted a couple of numbers into my email. I didn’t realise it, but these numbers were in fact hyperlinked in the document from which I’d copied them. As soon as I deleted the hyperlinked version and just typed in the numbers, the email went. So just a thought – check whether anything in your email is an actual hyperlink to an external doc before you try to send it!

  67. Dear Sir,

    Have a nice day.

    I migrate my data from one PC to another the old one was with XP windows as well Outlook 2003 while the new one is VISTA with Outlook 2007.Im receiving messages normally but not able to send any, is there any changes in account settings that I should change?

    We checked our servers and I put the same settings on many other computers and it works normally putting in consideration that the PCs we tried are all having WINDOWS XP and OUTLOOK 2007.

    Is the problem from WINDOWS VISTA?

    Note: All the copies we are using are GENUIN

    Thank you very much for your support & looking forward to hear from you soon.

  68. Use-fix outlook 2000 contacts list,
    program, that is 100% compatible with Microsoft Exchange Server, that is why it represents one of the most popular mail clients,restore all emails, contacts, messages, tasks and calendars are stored on server, not on your PC,recover contacts from ost, repair contacts Outlook and restore all data, that was considered to be lost,can become seriously damaged after hacker or virus attack, that’s why, your mailbox, as well as all other mailboxes, can be deleted and recreated,can export contacts to *.vcf files, that can be exported to Personal Information Management (PIM) tools or Windows Address Book.

  69. Hi there, I found the solution for you users with Vista and Outlook 2007: (this may not be a router issue, but your ssl logon settings)

    The reason the outgoing emails are not working is because the domain uses ssl authentication to verify your login. This protects your password during each authentication. Follow the steps below to make it work.

    To locate and verify your email settings in Outlook 2007:

    1. Click on the Tools menu in Outlook.
    2. Click on Account Settings.
    3. Double click on the email account that needs to be fixed.
    4. Set the “Incoming mail server (POP3)” to
    5. Set the “Outgoing mail server (SMTP)” to
    6. Set the User Name field to your full email address [email protected] and password.
    7 Check the password checkbox to remember password.
    8 Uncheck the “Require logon using Secure Password Authentication (SPA)” box.
    9. Click the More Settings button.
    10. Click on the Outgoing Server tab.
    11. Check the box next to “My outgoing server (SMTP) requires authentication”.
    12 Select the radio button “Use same settings as my incoming mail server”.
    13. Click the Advanced tab.
    14. Check the “This server requires an ecrypted connection (SSL)
    15. Select “SSL” from the “Use the following type of encrypted connection”.
    16. Enter Incoming mail (POP3) port 995 and the Outgoing mail (SMTP) port 465.
    17. Click OK.
    18. Click Test Account Settings. You should now get “Congratulations! All tests completed successfully.” message
    19. Click on Close.
    20. Click the Next button.
    21. Click the Finish button.


  70. I installed ATT Wireless (mercury) on my pc and have not been able to send emails since. ATT support says it’s a ‘outlook express thing’ not with them. I have tried every suggestion from microsoft and here on yahoo to no avail. Microsoft will hook me up with Tech for $60!:-(
    It’s driving me crazy as I know it is something stupid that needs to be tweeked.

  71. Thanks dude! I’ve been having the same problem with my isp as well. I have a Linksys WAG54x router – what a nightmare, you should sell this service to the poor service the ISP’s cannot offer!

    Fixed mine so thanks again!

  72. I need help. I’m runing Outlook 2007 on Vista and I cna’t sent email. I have the right setup and the tech looked at it and evyerhting is fine. He said I need to change the port numbers to 995 and 465 but when we do that, it doesn’t receive any mail. I can keep it the way it is (110.25) but he said i will keep receiving emails from yahoo that I need to use SSL. HELP! I have the wireless router from ATT

  73. Another one searching for a cure.

    We have 3 brand new Dell Optiplex 755’s on which XP & Office 2007 (including Outlook 2007) was in installed. Current info/settings were transferred from the older machines to these. Two of the 3 send and receive emails just fine. The third one, mine…can only receive. Any email I attempt to send sits in the Outbox until I get fed up and delete it.

    So far, I’ve been on the phone with our webhost, AT&T, who tested from their end… Nope, not their problem. Knew that because I’d already tested using the webmail feature. They sent me over to another section of AT&T whose tech recommended that I replace the SMTP with our physical IP address and change the port on the outgoing server.

    I have tried all of this and any combination I can think of, however, the emails still sit in the outbox.

    Why would the exact same (old) settings work on 2 other matching machines, yet not this one?

    I’m really frustrated with this and am hoping that someone out there has a solution.

    Thank you!


  74. Tamara,

    It sounds like you may have imported Outlook contacts from the other computer. I posted this a while back, but this process continues to work for me every time, even with new contacts imported from syncing with my handheld. To see if this relates to your problem, try to send an email to an address that is not in your address book. If it sends okay, then this might be your problem, too.

    For any message sitting in the outbox, double click on the recipients name, opening the contact box. Save and Close the contact, then hit send and the message should go. Works for me every time. Something weird about how 2007 imports contacts.

  75. Hello Bruce!

    Yes, I imported my Outlook files using ABF Outlook Backup that was provided to us by an outside IT company. For both of my bosses, this transfer worked without a hitch. They’re not having any issues and they have matching machines to mine.

    I had tried your solution and unfortunately, the msg is still in the outbox. You see in the corner where it says Send/Receive Complete and it gets your hopes up for a few seconds 🙂

    I have even uninstalled/reinstalled Office and manually set up my account without transferring and it *still* doesn’t send.

    Do you think I should simply delete the address book and start over from that angle?

    Thank you so much for your time and suggestions!


  76. I need help with Outlook 2007. I’m not having trouble sending email, but receiving. I always get the error response “receiving reported error ((0x800300FD) unknown error: 0x800300FD”. I noticed that my wife’s pop and smtp server settings were different than mine (when they weren’t before)? She’s receiving emails fine and not getting this error. I still get the same message after changing to her settings. No matter what settings/variations I’ve tried – I still get the same thing. Some emails seem to trickle in now and then, but I know I’m not getting all of them. Can you HELP me please!

    Thanks in advance.


  77. Bruce,
    I having searched and searched for hours for a solution to my problem of also not being able to send e-mail in which many (but not all) e-mails were being stuck in my outbox (since I installed Office 2007), and tried your method of opening and saving all contacts in my list. I sent a message to several people as a test and it worked. It was sent with no problems. Thank you very, very much.

  78. Certainly solved my problem with Vista and Outlook 2007 not sending, now all I have to sort out is why Internet Explorer7 will not go to BTYAHOO webmail?? over the wireless connection, Firefox works ok??? I am using a Belkin ADSL Wireless modem router

  79. In Outlook 2007, Select “Tools” from the menu, go to “Account Settings” Click on the e-mail account you want to work on. Click on “More Settings” and then the “Advanced” tab. Try changing your Outgoing Server setting from 25, which is the default seting for most ISPs to 587. Many ISPs offer his setting as an alternative to the default setting of 25. Follow the rest of the set up instructions per your ISP. Same concept for other Outlook versions, just may have to go about getting to that screen a little differently. Worked for me.

  80. Many thanks for the advice. I just got Office 2007 and Windows Vista. I set everything up as with Windows XP and had exactly the problem you identified – I could send but not recieve. You note above was extremely helpful and saved me many hours of frustration. Thanks again.

    Spent a couple of frustrating hours trying to figure it out and then I found this and I unchecked the stupid little box—WoooHooo!! Problem solved 🙂

    Now one other thing I can’t figure out is why Outlook 2007 (on Vista) keeps downloading “new” messages that I have already received!! Anybody encounter this problem??? My inbox is blowing up…

  82. I’ve had the email not send off and on with Vista Ultimate and Outlook 2007 and ATT — I’ve learned to expect it to go bonkers every once in a while.

    What am having trouble with the Outlook 2007 running on Vista Ultimate are the constant crashes!

    Outlook won’t open, the little message says that something happened to the file and it’s repairing itself which may take up to 24 hours or more to do. I’ve used Outlook Tools 2.1 to repair and many times that doesn’t work. I’ve deleted add-ins and still it doesn’t make a difference.

    I’m really stuck. This crashing can go on for 3 days before it fixes itself and works again. Any solutions? I’m going crazy!


  83. I could receive mail but not send using a newly set up email account on outlook 2007. Very frustrating. Now this might have already been said in this thread but I had to change a setting where I needed to CHECK – My outgoing server (SMTP) requires authentication.

    Tools – Account Settings – Account – (double click on email acct)- More Settings – Outgoing Server Tab, CHECK: “My outgoing server (SMTP) requires authentication” – CHECK: “Use same settings as my incoming mail server”

    Now it works fine.

  84. Mt laptop can receive email but cannot send. The laptop has Vista, Email Outlook 2007, and connect to internet through Linksys router WRT160N. Can you please suggest solution to sending email.

  85. In this situation advise try-password recovery tool pst,because this tool helped me many times and as far as i know it is free,program will help you to retrieve account details and service information, when necessary,can recover your forgotten password in several seconds,tool features a powerful algorithm, that permits to sorts all characters, including even multilingual alphabets and Unicode and composes another password for you, that will be accepted by Microsoft Outlook,will work under all supported versions of Microsoft Windows and Microsoft Office.

  86. Just wanted to thank all those who contributed to the blog post.

    I have a laptop and desktop both running vista (32 bit) and Outlook 2007. This morning my desktop decided to stop sending email, while my laptop continues to do so. Perplexed by this I checked and both machines have the same settings. The following were the steps I used to get the desktop working again:

    1. Confirmed my email server (Time Warner North Dallas, TX) at
    2. Launched Outlook 2007 and went to Tools > Account Settings
    3. Located to the Road Runner account and double clicked on it
    4. Clicked on More Settings control
    5. Clicked on Outgoing Server and made sure the My outgoing server (SMTP) requires authentication was de-checked
    6. Clicked on the Advanced tab and changed the value of the Outgoing server (SMTP) is set to 587
    7. Click on Ok to close the More Settings window and then Next and Finish to finalize

    The rest was history for me as everything began working as expected again

  87. Thank you Ian! This has been driving me crazy for months. I run outlook 2007 with Windows Vista and have not been able to send emails. I CHECKED the “My outgoing server (SMTP) requires authentication” box and suddenly I could send emails.

  88. Two computers running XP, One desktop & one laptop….linksys router, desktop pc wired to router & laptop wireless to router. Desktop pc will not send or forward emails with attachments,I am using outlook express & have tried switching to outlook with no change. All email settings are the same on both machines, running same antivirus (avast).
    Hughes satelite is my Isp. I can go to their webmail page…send & forward with attachments with no problems. Have bypassed router & no change. Any ideas why laptop can but desktop cannot??

  89. My OUTLOOK 2007 developed a similiar problem in that suddenly and unexpectedly my emails in the Outbox wouldn’t be sent. Receiving emails was OK. So, if you are using COX HSI, that ISP does NOT use authentication, and you should UNCHECK the “My outgoing server (SMTP) requires authentication.” Cox HSI uses smtp.(area) where (area) could be east, west, north, south. You can usually use any of those, not just where you are located. Unchecking the box, though, should fix “send” problems. Cox will not tell you this because they say they don’t have a “license” to provide technical support for Microsoft products.

    Of course, other ISPs may have different rules, so you can try both a check and an uncheck authentication.

  90. Please help. I’ve been using Outlook Express 2007 and I could send and received just within out company email ( but everytime I send to any with yahoo account it bounced back as in error. Is there any way I can send to other account such as yahoo, hotmail, gmail etc so that I’ll just use and manage one email add?

  91. Chris, I followed all your instructions but I still can not send mail. It gives me this message “Send test e-mail message: The connection to the server was interrupted. If this problem continues, contact your server administrator or Internet service provider (ISP).”

    Please help


  92. Help, please! I cannot send or receive email using Outlook 2007 after installing 2007 Microsoft Office Suite Service Pack 2 (SP2) update on May 8, 2009.

    My ISP is AT&T. I use a Two Wire wireless router. I’m running Windows Vista and Trend Micro PC-cillin protection. I spent hours on the phone last night with AT&T techs who made sure my POP3 port setting was “995” encrypted SSL connection and my SMTP was 465 SSL. They also made sure i checked the box “leave a copy of messages on the server.”

    I can send and receive messages with AT&T Yahoo webmail as well as Outlook Express (or whatever it’s called in Office 2007)just not in Outlook 2007.

    Any suggestions?

  93. im having a problem with multiple email addresses using outlook 2007. worked fine and the desktop fell ill. sent it to be re formated and now it wont work. when you start it up it shows send recieve status at the bottom and opens one new email, then comes up that its encountered a problem. it will allow me to send emails fine solong as i cancel the send recieve as soon as i open it. this has been going on for about 3months now, any ideas??? running window xp sp2

    my apologises if i havent been specific enough as im still new to this.

  94. Vista blocks port 25 (used for sending emails through Outlook) if your IP address is Dynamic.
    Change your IP Address to Static, it will open up the port 25 and emails will go out.

  95. Bikram,

    Do you have any facts to back up this statement?

    You wrote: “Vista blocks port 25 (used for sending emails through Outlook) if your IP address is Dynamic.”

    I don’t believe this to be true. I have several machines successfully running Vista with Outlook and my IP is dynamic.

    Please validate your statement, lest our poor readers be misinformed…

  96. I cannot send emails in Outlook 2007 but have no problems receiving mail. I have tried every suggested listed in these communications and have spoken with tech assistance for hours but no-one seems to be able to resole the issue. No error messages come up when I hit the send/receive tab and it progress shows all tasks completed successfully. Test Settings work fine but sending a test message in outlook does not leave the outbox and remains unsent. This is driving me crazy! Can anyone help??

  97. My original (long) solution did not post correctly so here’s a short version: Problem: emails suddenly wouldn’t send/receive in Outlook 2007. I have XP, Comcast, Linksys wireless. Tried most of above suggestions but didn’t work or problem returned. What did work was to create a new email account in Outlook (using email address of “broken” account). I accepted defaults but checked “Keep copy on server”. Email has been moving in all accounts since then. I will delete new one.

  98. Here is Colleen’s original long post. Thanks for sending it in. Hope this can help others out there with the same issues.


    I had the same problem as described by Don Williams (July 3, 2007) and tried most of the above suggestions. Outlook 2007 was working fine for 6 months and then suddenly it gets bogged down so that I can’t send or receive. Mail eventually comes through (sometimes), but after hours, and it’s not reliable at all. I have Comcast ISP, Windows XP sp 2, wireless, linksys router, cable modem. The frustrating part is that I could shutdown all PC’s (in home network), turn off linksys router and cable modem, wait 2 minutes, bring everything back up, still have to select “repair” on my wireless icon, and sometimes this would fix my email, but the problem would return. What finally worked for me (hope it lasts) is that I added a new account in Outlook 2007 and this got the mail flowing again. The “new” account is the same as the old (broken) one. Of course, it automatically downloaded 800 emails from the server (duplicates of what’s in my inbox, basically), so I manually deleted them in Outlook. Then, suddenly, my old account started working, so I was receiving duplicates of emails. I just disabled the “new”
    account from the Send/Receive Group so I wouldn’t get duplicates. Just remember that all emails left on your server will be downloaded, so you may want to clean up the account first on the server. I hope this wasn’t too confusing. Here are the steps to add a new (replacement) email account in Outlook 2007:

    Account settings –> New–> (take all defaults): Microsoft Exchange, POP3, IMAP, or HTTP –>NEXT –> (Enter you name, email address and password. It can be identical to the account you are replacing, if you want). Do NOT CHECK “Manually configure server settings.–>NEXT. Once it returns, If you want to keep a copy of all your emails on the server, then you need to do one more step, otherwise, after your emails are downloaded to OUtlook, they will be deleted from the server automatically!! So, if you want to keep a copy of your emails on the server, check the box at the bottom of the screen to “Manually configure server settings” then click “NEXT” Click “More Settings” –> “Advanced” –> and check “leave a copy of messages on the server”–> OK–> FINISH.

    Then, you will need to add this account to the Send/Receive Group in Outlook. Click on the “down arrow” to the right of the “Send/Receive” button on the Outlook toolbar (to open up the menu). Select “Send/Receive Settings –>Define Send/Receive Groups–>Select a group to Edit (or add a new group) and make sure this new account is added to a group. I think this is a problem with Outlook 2007 because I don’t have any problems getting mail directly from Comcast webmail on any of my home PC’s.



    – Hang opening e-mail with attachments > 100KB.
    – Stuck in Outbox sending e-mails with attachments > 100KB. I get the following…

    Error (0x800CCC13) : ‘Cannot connect to the network. Verify your network connection or modem.’


    Operating System: Windows 7 Pro
    Email Client: Outlook 2007 (SP2)
    Linksys Router: WRT54G
    Email Address:
    SMTP Setting: (IMAP incoming)
    SMTP Port: 587 (TLS encryption)
    ISP: Cox

    I removed all Outlook Add-ins.

    I’m 99% sure this didn’t used to happen. Something must’ve changed, but I don’t know what. Any suggestions?

  100. THNK U SO MUCH!!! I did the account settings/authentication thing and it WORKED! UR A WONDERFUL PERSON!!! thnk u thnk u thnk u! my computer just wldnt send out emails, but it used to……. i ddnt understand wat was wrong?! BUT U FIXED IT HOORAY

  101. Thanks for this article. I have sign only certificate but Outlook is not sending the signed e-mails using this certificate? Any solutions to this or this is not valid use case i.e. my certificate should be both sign and encrpt.

  102. WoooHooo! After hours or mucking around, uninstalling and reinstalling, upgrading from Outlook 2003 to Outlook 2007, recreating profiles and lots of import/export, I have finally over come my problem where I was unable to send attachments. I thought it was Antivirus holding up the email, not allowing it to be sent, as a text only email would send OK but not if it had an attachement.

    I am posting here to tell you all I have finally fixed my problem, and I hope it fixes yours too. First, heres what I did to no avail:
    Delete and make new profile
    Export everything and import into new profile
    Run Norton Removal Tool (even though I have never had Norton)
    Upgraded from Outlook 2003 to 2007
    Delete contacts
    Uninstalled Antivirus
    Disabled Firewalls

    and still could not send an email with an attachment. I found this site here: which talks about running a Command in the CMD prompt

    netsh interface tcp set global autotuninglevel=disabled

    I did this (had to open CMD prompt as Administrator in Win 7) while my Outlook was closed. I then opened it back up, forwarded an email with an attachment and it sent no dramas!!!

    THIS FIXED THE PROBLEM FOR ME!!! Before now I have seen the problem 3 times on XP, Vista and Win 7 machines, and previously I wiped them all because I couldn’t fix it. See how this goes and let me know!

  103. Thank you so much! That was such a simple fix for my outlook outgoing mail problems I’ve been having for months. I really appreciate your great advice!

  104. whenever i email someone with a gmail address it goes to an unkown address.
    what hsould i do to correct this situation?
    i have windows 7 ultimate with office 2007.
    thanks for your help.

  105. I’m sure you get this all the time, but thank you all for the support. My problem has been resolved and it was due to using my ISP settings for the “outgoing” server. For the record, I have Vista, Outlook 2007, linksys router…..Thanks again

  106. VERY STRANGE PROBLEM-I can not send emails using Outlook 2007 when I have more than two recipient email addresses, one is fine, two is fine, three addresses gives me a not responding error and have to close Outlook-have tried many fixs, no luck, haven’t reinstalled or tried Outlook repair cd yet.Thanks to anyone.

  107. I have some problem. every day morning our company people come they will mail is not going.I will go and reset modem after is going. This is more two month going any soloution is there

  108. Uncheck the Require logon …Authentication (SPA)

    My outgoing server requires Authentication
    – Use same settings as my incoming mail server

    Incoming Server (POP3) : 995
    – Check ==> This server requires ….
    Outgoing Server (SMTP) : 587
    – Auto

    Leave a copy of message on the server

  109. I am out of town on vacation and am getting internet and incoming emails but cant send emails in outlook. I tried all of the above but keep getting an error message saying smtp timing out waiting for a response. I changed and tried different smtp’s but nothing. I can use webmail in the meantime but would really love to use outlook as I normally use everyday when back home.
    Any thoughts?

    outlook 2007
    vista business
    not sure of router as I have no control over it even if I knew it.

  110. Hi, I still have a problem of sending mails from Outlook2007. I configured that XP Machine on VMWARE 7.0. Outlook is configured with POP3 Account and the network is on NAT.

    Please Help me.


  111. I keep getting this message when trying to send out mail using Outlook 2007 and I have mozilla as a browser. can anyone help me out on this?

    The host ‘’ could not be found. Please verify that you have entered the server name correctly. Account: ‘’, Server: ‘’, Protocol: SMTP, Port: 465, Secure(SSL): Yes, Socket Error: 11004, Error Number: 0x800CCC0D

  112. A life saver! After looking several other places, your answer was precisely what I needed. After updating my Outlook to the 2007 version, messages to be sent congregated in my outbox, and nothing seemed to fix the problem. Your suggestion to look for and check the “Require Secure Password Authorization” box (following 6 or so sub-dialogue box levels!) was the fix. Thanks so much. Give yourself a firm pat on the back for me!!

  113. @George, try this.

    First close outlook.

    Then in your computer goto:

    C:\Program Files (x86)\Microsoft Office\Office12

    Look for the Outlook.exe, right click and choose “Run as Administrator”

    In Outlook, goto Tools -> Trust Center -> Add-Ins

    At the bottom of that window click on the Manage: COM Add-ins “Go”

    Disable any frivolous add-ins, specifically antivirus add-ins. Leave the add-ins created by Microsoft or Windows.

    Restart Outlook and see if that works. My issue it seems was caused by an AVG add-in or an AdobePDF add-in. I disabled both and it seems to have cleared up the issue. Though I suspect the culprit was AVG.

  114. Running Outlook 2007 on Vista with AT&T DSL….

    I had this problem too and wanted to put in what worked for me. My problem was that I had two email accounts one from my 3rd party website and one from The 3rd party website sent and received email fine. My account received email but would not SEND email. Further until about a month ago this problem was INTERMITTENT at best. Until one day it just stopped working period. The account stopped receiving and sending email.

    The entire time I received this error message:

    Task ‘Lydia Marcassa – Sending’ reported error (0x800CCC0F) : ‘The connection to the server was interrupted. If this problem continues, contact your server administrator or Internet service provider (ISP).’

    After tons of research and performing the following things:

    1. Checking and rechecking the sets up for my email account. Doing a registry scan and clean (one site suggested a registry scan and clean would help)

    2. Deleted and re-set up the email account, 2x.

    3. Ran a scan and clean of registry set up.

    4. Ran a scan and clean for any possible viruses.

    5. Logged on to my AT&T webmail account and verified that it was working properly. AT&T help line suggested that if this is NOT done then problems will result.

    6. Exporting all my old email and deleting them (one site suggested that a strange email might cause this issue)

    7. I uninstalled and disabled all web protection, virus scan software. ALL because several sites suggested that it was a problem between these programs and their set up affecting Outlook and AT&T.

    8. I started it in safe mode after doing all this and nada.

    9. I uninstalled and reinstalled Outlook 2007 and then reinstalled all updates from Microsoft.

    10. I re-set up my accounts. Again my third party account continued to work and somewhere along the line my receiving began to work.

    11. I stumbled upon an AT&T forum regarding this issue not only affecting Outlook but MacMail and Windows Live. AT&T spewed bs; however, the other members on the forum suggested three things:

    …1 Unselected the “My SMTP requires authorization and use my incoming settings.”

    Did this and nada.

    …2 That the problem might originate from not authenticating the YAHOO email. So I logged onto the YAHOO email and selected options and verified my email account.

    Did this and nada.

    …3 That the problem originates from the settings on the Advance tab. AT&T suggest that you set the Incoming Pop3 settings to 995 and outgoing to 465. I was suggested to change the outgoing setting to 587. I did and….

    I began to send email and stopped receiving it! (yes, seriously)

    SOOOO – I changed the incoming pop3 account setting to 110, the default and…

    Now everything works. Who knows the mind of AT&T? Certainly not me or the days I wasted trying to make this work.

    To be clear: I set my Incoming Server (Pop3) to 110 and my Outgoing Server (SMTP) to 587 all on the advance tab setting in Outlook under account settings for the AT&T account.

    Just wanted my solution out there.

  115. Hi there, I followed loads of the advice on this post as my outlook 07 suddenly stopped sending emails (but was receiving). Nothing worked for me until I created a new account.In the end I deleted all my accounts (four) and recreated them exactly the same as advised by
    ‘By Colleen on Jan 12, 2010 | Reply

    My original (long) solution did not post correctly so here’s a short version: Problem: emails suddenly wouldn’t send/receive in Outlook 2007. I have XP, Comcast, Linksys wireless. Tried most of above suggestions but didn’t work or problem returned. What did work was to create a new email account in Outlook (using email address of “broken” account). I accepted defaults but checked “Keep copy on server”. Email has been moving in all accounts since then. I will delete new one.’

    Everything works now as it should 🙂

  116. Have the same problem, but managed to fixed it.
    Go to: Tools –>Option–>Mail Setup Tab –>Email Account, then click on Repair. It will solve the problem

    Hope this can help


  117. Chris, your the best! worked for me, after suffering for 2 weeks of not being able to send email!!!!!! Using Oulook 2007 and Vista!

  118. You are a genius! Thank you – for the first time in 4 months I can send my personal mail from Outlook 2007 without switching to that horrid winmail. Thank you

  119. Great article thanks – this has saved me a major headache.

    However I dont think my problem had anything to do with the router, just the fact started using new ISP and had to adjust SMTP settings with their version. Also the all important unchecking of outgoing authorization button fixed the problem.

  120. Boy, You are just so good. Thanks you’re the best honestly. it just worked like magic for me though i just clicked on REPAIR and that’s it, all sorted out. You just gave me a clue. i can send and receive messages at the same time.

    Thanks once more.

    c i a o!!!!

  121. thanks but there is a messages after i send.

    Undeliverable: Commercial Offer & Catalogues
    System Administrator.
    Your message
    To: ‘[email protected]
    Subject: FW: Commercial Offer & Catalogues
    Sent: 11/17/2012 10:49 AM

    what should do???


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