• Curran@CurranOmniMedia.com

How To Fix Your Port Settings If Cannot Send Mail From Outlook

How To Fix Your Port Settings If Cannot Send Mail From Outlook

Almost all mail client program send e-mail using port 25, which is also the port used by mail servers to talk to each other. But port 25 is widely abused by malware to spread worms and spam. As a result, many ISPs are restricting its use.

Hang on – it will make sense in a second:

Most people having a setup where they are on an Internet Service Provider (ISP) like ATT and have an email address like “MyEmail@ATT.net”  You connect to the internet using ATT and send mail through the ATT server – no problem.

But if you have your own domain email address or an email address from another ISP you may hit a snag. In these cases you are connecting to the internet through your ISP (like Comcast, SpeakEasy, ATT, etc) and trying to send email through your third party host like “MyEmail@SuperCoolWebsite.com”

Your ISP says “Hey! There is someone on my network trying to send email through someone elses address! This might be spam or malware!” You can receive mail, but you can’t send mail.

Recently ATT and Verizon both made changes that affected outgoing mail. Here’s the fix:

If you cannot SEND MAIL

  1. Open OUTLOOK
  2. Select TOOLS
  4. Highlight the account in question and select CHANGE
  6. Select ADVANCED
  7. Change from PORT 25 to PORT 587
  8. Save everything and restart Outlook


Other email programs will have similar settings. Look for PROPERTIES or PREFERENCES and find the outgoing mail server option.

One other option to check is that you are authenticating before sending. In other words. logging in with your username and password to both check and send email.

In Outlook the options window looks like this:


This tells Outlook to send your username and password before trying to send mail. If you have problems try enabling or disabling this setting.

The screen shots used in this how-to are my actual settings and they work just fine with SpeakEasy and ATT.


  • JOHN_B1

    April 19, 2009 at 11:45 am

    Wow where did you get this info from. It works, but those people from ATT who aren't even in this country keep on telling me to use 465 which doesn't work. Thanks again.

  • Betsy

    May 16, 2009 at 5:46 am

    Thanks for the quick reference! I'd found a site with this information some time ago, but did not bookmark it. I appreciate the screenshot, and enjoyed your explanation of the issue! 🙂

    Iain Cox

    October 3, 2009 at 7:41 am

    Many thanks for this post Daniel. It helped resolve an email problem that was causing me some frustration. Easy when you know how!


    January 9, 2010 at 3:13 am

    Great post!!
    I was also facing the same kind of problem in my laptop when I travel to other countries than i'm.
    Then I got a miracle solution which really worked for me.
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    February 4, 2010 at 10:44 pm

    Thanks a ton! ATT couldn't even figure it out.

    Josh Lucas

    February 26, 2010 at 3:13 pm

    Thanks a lot! Comcast was of no help a all (big surprise)


    March 8, 2010 at 12:07 am

    Thanks so so much..


    June 27, 2010 at 5:21 pm

    Thank you sooooooooooooooooooooooooo much ! It worked.


    July 21, 2010 at 5:08 am

    my outlook receave but not send mails
    incoming mail (pop3)is
    outgoing smtp is
    & this same settings work proper in other pc
    but not wirk in default pc………………


    November 28, 2010 at 6:58 pm

    Great!!!! It works!!!! All I did was to change from Port 25 to 587. Thank you.


    December 16, 2010 at 4:59 am

    awesome! thanks

    So Happy

    February 25, 2011 at 11:44 pm

    Thank you very much! This worked for me with Qwest MSN email and I've spent hours trying to open port 25 on my new modem/router. Yaaaa!


    February 28, 2011 at 5:43 am

    good job!!!!!!!


    February 28, 2011 at 5:44 am

    i've been trying to figure out what to do you save me from alot of pain tnx alot!!!


    March 29, 2011 at 9:15 am

    I was really getting frustrated. Thanks so much for a good quick fix!

    Erin Doom

    July 13, 2011 at 6:19 am

    Port 587 doesn't work with Mac. I've tried 993, 465, 25 and now 587. Any suggestions?


      January 16, 2012 at 11:49 pm

      the port that worked for me was 26


    August 5, 2011 at 8:15 pm

    this was great, thank you! Worked perfectly!


    September 2, 2011 at 5:18 pm

    Nice to be visiting your post again, it has been months for me. Well this article that I’ve been waited for so long. I need this article to complete my assignment in the college, and it has same topic with your article. Thanks, great share!

    Louboutin Discount

    September 2, 2011 at 11:43 pm

    I am very interested about it, will you share more detail? Like source of this story

    Ugg Winter Boots

    September 7, 2011 at 11:34 pm

    Thanks for your sharing, I like your article, looking forward to your next to share.


    September 15, 2011 at 2:11 pm

    thankyou very much, big pat on your back from me!!!! back to business!!!


    November 23, 2011 at 4:52 am

    Awesome….The only question I have is, "when i leave the at&t network at my house, do I have to switch back to Port 25 at my office


      January 16, 2012 at 11:48 pm

      No, you don't have to change it back.


    January 11, 2012 at 7:09 pm

    thx macha


    January 16, 2012 at 11:46 pm

    For all the people in the MAC world, the port that worked for me was 26.

    Gabrielle Talley

    February 3, 2012 at 6:29 am

    THANK YOU!!! I've been trying to figure this out for the past 2 months. Had to use my ATT email account to send messages. It was a pain going back and forth from Outlook to ATT, copying and pasting. Plus the emails would come out with different fonts, I wasn't able to insert pics into the body of the email…. ugh! Your settings helped so much. Feel free to use this as a testimonial for your services… Gabrielle Talley


    February 3, 2012 at 2:13 pm

    I am trying to set up on an android tablet with AT&T email and I am using
    username: myemail@att.net
    password: my password
    pop3 server: att.net
    port: 587
    and its not working….what am I doing wrong?

    Tamar Massie

    April 17, 2012 at 2:44 am

    The screen shots used in this how-to are my actual settings and they work just fine with SpeakEasy and ATT.


    April 18, 2012 at 12:22 am

    Almost all mail client program send e-mail using port 25, which is also the port


    April 19, 2012 at 1:58 am

    Almost all mail client program send e-mail using port 25, which is also the port used by mail servers to talk to each other. But port 25 is widely abused by malware


    April 27, 2012 at 10:05 pm

    You connect to the internet using ATT and send mail through the ATT server – no problem.

    Charles Wilson

    April 28, 2012 at 2:12 am

    As a result, many ISPs are restricting its use


    April 28, 2012 at 2:38 am

    You connect to the internet using ATT and send mail through the ATT server – no problem.

    Zandra Earley

    April 30, 2012 at 11:07 pm

    You connect to the internet using ATT and send mail through the ATT server – no problem.



    May 17, 2012 at 1:39 am

    Fantastic Fix! Many Many Thanks Daniel


    August 29, 2012 at 12:02 pm

    I have a MAIL.COM email account that I cannot access on my phone with the constant error message "Unable to connect to server". I have tried the incoming server security of SSL (Accept all), with port No, 995, 993, 587, & also 26, but none of them are allowing me access.

    My outgoings server security is SSL (Accept all), with port No. 465, but again I have tried several other port numbers, but nothing I try is playing ball, so any help/assistance that you can provide will be gratefully appreciated please to use with the Android mobile phone email settings of my Mail.com account.


    September 4, 2012 at 1:01 pm

    YEAH! It worked, every other site had 465 or 25 or something else!

    l vicent

    January 8, 2013 at 2:17 am

    Your feed back on Authenticating before sending works great ,not even my ISP (Comcast) Tech support was not able to correct the issue,they are using a Third party -Tech Support called Advance Tech Support if you ask for the Service you will be charge a one time feed of $55.00.your knowledge puts all of them to shame my Outlook is working fine after following your steps -thanks once again Curran JR

    Le dicen MAD.

    January 23, 2013 at 10:25 am

    Worked for me. Excelent ! Thanks !


    January 30, 2013 at 1:27 am

    It worked for me but mails all bounced.


    February 8, 2013 at 7:24 am

    Best advice I received….worked like a charm


    February 9, 2013 at 11:33 am

    Thank you so much Daniel, I had the problem for about a year. First I asked a specialist and that proved naive, then I searched the internet and for some reason did not find your post.
    And today after a year of sending mail only from home, and one full week of anger sending mail from my webmail instead of using Outlook, you solve my problem.


    March 8, 2013 at 2:46 am

    bro you great it works perfectly thanks alot


    March 8, 2013 at 11:14 am

    Thank You! Perfect!


    March 17, 2013 at 9:39 am

    This has been bugging me forever. THANK YOU!


    March 26, 2013 at 10:27 pm

    I’d like to thank you for this reference, I actually work for a U.S AT&T department and lately we’ve seen this issue pop up more often. My first customer was frustrated and I used this to help come to a resolution and it worked like a charm. I’ve referred a few customers to this website just in case this problem comes up in the future and they’re so happy. A lot of us are using this so we don’t have to send customers to another department that charges a fee to help.

    Again, thanks a ton!

    rama naidu

    March 31, 2013 at 1:54 am

    not find that

    Harry Houdini

    April 15, 2013 at 4:10 pm

    Dude you rock! I just fixed my Outook after wrestling with it for 3 days. Comcsst guys had zero idea how to help. Thank you! My only wonder is why this suddenly became a problem for me. Well, anyway, I am now happy.


    May 24, 2013 at 1:01 am

    Love, Love, Love you. So helpful. Comcast kept telling me to use 465.

    Attres Tagge

    March 31, 2014 at 6:26 pm


    Unfortunately, this did not work for me. I am living in Bogota, Colombia and have ETB as my internet service provider; however, I use a cox.net email address. When I first arrived my port 25 worked from August 2013 – October 2013. I googled the issue and found a site that recommended port 465 and it worked up until last week I have tried all of the port numbers mentioned in this thread to no avail. HELP!!!!!!

      Daniel Curran

      March 31, 2014 at 9:21 pm

      I think at this point you need to call your ISP and ask them what to do. If the standard and backup ports aren’t working then they owe you an explanation.

    Bruce Lenihan

    July 9, 2015 at 6:11 am

    I live in France and have Orange as my ISP. Outlook was working perfectly for years the a few days ago I could receive emails but not send. When I log into the Orange site, I can send emails. I changed from 25 to 587 and it worked one time then it stopped working. I’ve tried changing to all these other numbers (25, 26, 465, 587, 995, 993) but nothing works…any suggestions?

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