I-Thunderbird Community Forum

I open Thunderbird and click on get messages and emails are not coming into Thunderbird from AT&T. It worked perfectly yesterday but today we are encountering this issue. There was no changes to the application since yesterday. Thunderbird is online I clicked the icon at the bottom it shows when it is offline. I contacted AT&T and they said things were working on their side. What are possible things I can do to fix this issue

when trying to download email today, says certificate for inbound.att.net is not trusted. android email and browser email are OK.

I keep getting this message: "We've identified a site certificate problem, trust for this certificate has been revoked." The location is "inbound.att.net" So I can't receive any E-Mails on my PC, but I can on my phone. How can I fix this?

I get "connection to server pop.mail.yahoo.com timed out" every few minutes. mail is not usually delivered, and some mail that's delivered is from two-three weeks ago that I've already gotten. It seems that I've stopped receiving mail for account "redacted@frontier.com" after 10/8/26. Mail that's sent to other accounts seem to be delivered OK, but mail that's sent to this account doesn't show up. I've received at least some mail for account "redacted@frontier.com" for 10/9 and 10/10. Not sure if I'm getting everything. Mail seems to be received at the yahoo.com website for both email addresses [redacted@frontier.com and redacted@frontier.com]. At least I hope it is! Mail also seems to be received using the yahoo app for Android [phone] and yahoo app for iPad.

I like the new support for Outlook. Thank you very much. This was the first year that I did not spend >16 hours rebuilding accounts each January. It is also nice that this support automatically transfered incoming emails to the Local Inbox.

Just recently, Spectrum Internet dropped POP3 support and I was able to setup IMAP.

Gee, It would be nice if there was just one more checkbox in the Account Setup which would automatically transfer IMAP messages to the Local Inbox.

Can this be added to the wish list?

Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) mail.twc.com timed out. Try again.

I moved some emails to a folder and they are not there. Tried to move last email to folder and it jumps back to my inbox. Also how do I access help in thunderbird?

I have been using Thunderbird for my email for more than 15 years. About once ever few years a corrupted email file prevents me from downloading any more email. In the past I was able to use ftp to list email files on the pop server, find the corrupted file and delete it restoring my ability to download again.. It happened again on Oct 2 but I can no longer use ftp to access the files to fix the problem. IT appears that yahoo has fixed that problem in their email software but Thunderbird does not contain that fix. The bad file is somewhere in the first 4 to 10 files on Oct 2. It follows a file from American cruise lines.in my [redacted]@yahoo.com account using Thunderbird. I now have over 900 email files I cannot download using Thunderbird but can see those files using yahoo email software. Please fix Thunderbird.

I use a personal computer, and can access my email two ways: 1) By typing "att.net" into my browser and choosing email." 2) By booting up PC, typing PIN, then a 16-digit alpha password generated by ATT. Two days ago this function stopped working. Q: What can I do to again access my email via the ATT account? I called AT&T yesterday, and human advised me it was a Thunderbird problem.

And I don't know how to "...find my version in Thunderbird App menu as requested below.

Thanks!/rose

I recently set up Thunderbird for Windows as a troubleshooting step for my Yahoo Mail account which has been generating an incessant number of authentication pop-ups in Microsoft Outlook (Classic) for Windows. I had been using New Outlook for many months before switching to Classic Outlook a couple of weeks ago. With New Outlook, there had been no authentication issues nor pop-ups appearing. I have been using the OAuth authentication, not app passwords, in all cases.

Setup within Thunderbird was relatively easy and the OAuth authentication went through without issues. The account has synchronized and seems to be continuing to do so as I read, delete, and send messages.

However, when I went in to the Activity Manager, I'm seeing a number of errors, appearing every 10-15 minutes or so. They read as follows:

• Alert from account xxx@yahoo.com: AUTHENTICATE Server error - Please try again later

• The current operation on 'Inbox' did not succeed. The mail server for account xxx@yahoo.com responded: UID FETCH completed.

• The current operation on 'Inbox' did not succeed. The mail server for account xxx@yahoo.com responded: p.

Can anyone help me understand what they mean? It would help me stabilize Thunderbird and might give some clues as to what is happening in Outlook Classic for me. It would seem some have authentication issues with Yahoo on different platforms while the service works perfectly fine for others. I would like to move away from Yahoo as I find it finicky with a number of its features, but I'm a long-term user (25+ years) and don't see that being a practical solution at the moment.

Thanks!

Not sure what is going on but all of the sudden my inbound server is not allowing emails in. Outbound works. AT&T says its a Thunderbird issue. My computer guy cannot figure it out. Help. I can only receive email on AT&T

My eMail has worked fine for many years - until this morning.

 When I first tried to "get messages", I got a response, "connection to inbound.att.net server reset".
 I restarted Thunderbird, and then the computer (Windows 11), and when I tried again, I got, ""inbound.att.net (POP) .. certificate revoked".
 I can login to my ATT webmail, but I can't download eMail to my computer via Thunderbird.

... In my attempt to upload this question, I looked for the TB Version, but it said to update Thunderbird. I did so, not it is back to telling me "connection...reset"

 Please help!

Earlier today I was able to access my AT&T email using Thunderbird. I have several email addresses & they worked. But later on I could not download any AT&T email. Interesting that my gmail address still works with TB.

I tried a few things - An AT&T address can send to the gmail address & the gmail does receive it. The gmail can send to an AT&T address. The gmail indicates it was sent, but the AT&T address never receives it.

It seems to be an AT&T problem so I went to the AT&T site & deleted the Secure Mail Key an created a new one. Did this on just one address. It can still send to the gmail address, however it still cannot receive anything.

When trying to receive any AT&T email, at the bottom of the screen it displays my address & “Connected to inbound.att .net”. That would seem to indicate I'm connected but just cannot get my email.

And suggestions on how to get TB working with AT&T email? Thanks.

I am assisting an elderly user with a personal @hotmail.com account that receives email successfully in Thunderbird but cannot send. I have confirmed they can send and receive emails from their online outlook.com portal. The user's computer setup is as follows:

• Windows 11 (with latest updates).
• Thunderbird 153.0.2 (64-bit).
• A personal @hotmail.com account with the following server configurations:

  -> Incoming IMAP: outlook.office365.com, port 993, SSL/TLS, OAuth2, and
  -> Outgoing SMTP: smtp-mail.outlook.com, port 587, STARTTLS, OAuth2.

Thunderbird successfully authenticates to Microsoft using OAuth2 for incoming email. However, when Thunderbird attempts outgoing email authentication, Microsoft's SMTP server rejects the authentication. The Error Console in Thunderbird records this message: "535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox."

-> Refer to attached image: "Thunderbird Error Console_20260811.jpg". -> I am able to provide a short screen recording demonstrating the failure if needed.

To try and resolve the above, I completed the following actions:

1. Confirmed Thunderbird is current (153.0.2).
2. Confirmed SMTP is configured for OAuth2 rather than Normal Password.
3. Confirmed port 587 and STARTTLS.
4. Re-authorised the Microsoft account/OAuth connection.
5. Confirmed IMAP OAuth2 works.
6. Confirmed Outlook.com webmail can send successfully.
7. Reviewed Mozilla's current “Microsoft OAuth Authentication and Thunderbird in 2026” guidance, including the section covering cases where IMAP/POP works but SMTP does not.
8. Captured the SMTP failure in Thunderbird's Error Console.

However nothing worked, so I raised the matter with Microsoft support and eventually had the matter referred to their Tier 2 team. The Microsoft case number is: 7107041963.

Microsoft Support confirmed that for a personal Outlook.com/Hotmail account there is no user-accessible mailbox-level SMTP AUTH setting, and advised that SMTP is enabled by default for supported clients. However, because sending from Outlook.com webmail works, Microsoft Tier 2 declined to investigate the SMTP server response further and directed me to Thunderbird support.

I am able to provide a copy of the chat transcript if needed.

In any event, the TLDR version IMAP works using OAuth2, but SMTP using OAuth2 fails because Microsoft's SMTP server reports SmtpClientAuthentication is disabled for the Mailbox. Microsoft Tier 2 has referred the issue to Thunderbird support.

Questions:

1. Is this a known current issue affecting personal Outlook.com/Hotmail accounts using Thunderbird?
2. Is 535 5.7.139 SmtpClientAuthentication is disabled for the Mailbox known to occur with Thunderbird OAuth2 even though IMAP OAuth2 succeeds?
3. Is there a current Thunderbird-side workaround or alternative SMTP server/configuration recommended for personal Hotmail accounts?
4. Would changing the SMTP server from smtp-mail.outlook.com to smtp.office365.com be appropriate for a personal Hotmail account in Thunderbird 153, or should the current Microsoft-documented server be retained?

-> I note there appears to be conflicting advice on this point in previous support threads.

1. Given that IMAP OAuth2 authentication succeeds for the same Microsoft account, does this indicate that Thunderbird's Microsoft OAuth authorisation itself is functioning correctly, or could SMTP require a separate permission/token that may be failing?
2. Are there any additional Thunderbird logs or diagnostics I can provide that would help resolve this matter?

Disclosure: I used ChatGPT to help organise my troubleshooting notes and technical details for this post. The troubleshooting, observations and diagnostic information described above are from my own work on the affected PC.

I have lost mt SEND button when I want to send emails to others. This has resulted some time ago and is most inconvenient when replying to email's. How do I get it back?