Failed authentication error on Thunderbird using comcast/Xfinity email accounts
Have used Thunderbird with Comcast/Xfinity for over 10 years. I can receive all of my email on Thunderbird. About 6 months ago I started to not be able to send emails from Thunderbird sporadically, but it has escalated to the point of not being able to send emails of my comcast.net accounts at all. From my gmail accounts I can send messages just fine through Thunderbird. Three weeks ago I spent 2 hours on the phone with Xfinity. Reset all the passwords, checked all the settings, etc etc. For the rest of that day I could send all emails through Thunderbird. Ever since that day, same problem. I spent another 2 hours on the phone yesterday with Xfinity and they are sending my issue to a 3rd or 4th tier support person. They say there is no guarantee they will find a solution and that I won't hear back until Monday or Tuesday. Also this is the same problem on 2 different computers. One computer has the newest Thunderbird update to version 128.1.0esr and the other has the last version of Thunderbird as 115.14.0.
Here is the exact error message I get when I try to send an email:
Sending of message failed. An error occurred while sending mail: Outgoing server (SMTP) error. The server responded: resomta-s2p-647654.sys.comcast.net resomta-s2p-647654.sys.comcast.net Excessive failed authentication, ESMTP server temporarily not available.
The numbers after s2p- change for each attempt to send an email.
Believe me I have tried all sorts of different settings and I have read practically all of the solutions I could find on Mozilla's support forums and articles.
Really need help on this one. Jennifer
All Replies (3)
This is Jennifer again.
Xfinity just now called me back. It was a level 4 support person. ALL he kept saying was it is NOT our problem, you have to contact Thunderbird, over and over and over again and that the ONLY thing they can check on their end is to make sure the 'allow 3rd party etc' box is checked. Which it is and always has been on my comcast accounts. Very rude guy and absolutely no help at all. Not like the girl I got 3 weeks ago who helped me. To say the least, I am soooo frustrated that this problem persists, especially since I have used Thunderbird with Comcast/Xfinity email for years and years. Again I really hope someone can help.
Go into Thunderbirds passwords and delete all that are there for your comcast account. https://support.mozilla.org/en-US/kb/password-manager-remember-delete-change-tb
As comcast are disabling your access to the outgoing server (that is what the error message says) do not open Thunderbird after you reset the passwords for 24 hours. I assume their definition of temporary is 24 hours, but it is entirely a guess. It might just as well be an hour or three months.
Now after the time has elapsed you should again have access to comcasts outgoing server and as Thunderbird has no passwords to offer comcast when asked you will be asked. Do you still see the problem? If not, save your password and go on with life.
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