Форум спільноти Thunderbird

ever since last update... can't send emails

Send Message Error Sending of the message failed. An error occurred while sending mail. The mail server responded: E5rTxqhwZYbiPE5rUxBTZm DMARC Policy Enforcement: https://postmaster.comcast.net/smtp-error-codes.php#ODM00001. Please check the message and try again.

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

My @googlemail.com account has been working in Thunderbird for years. Two days ago it stopped. No incoming e-mails and attempts to send e-mails from Thunderbird result in the outgoing server timing out. I can access direct at gmail.

Please note that my previous e-mail: alan.rhodes@talktalk.net is no longer available The replacement: alan-rhodes@outlook.com has been blocked by MS-AI (It didn't like a circulation e-mail to 60 members of my local history group) The only working e-mail I have is the current problem one: rhodes.alan1@googlemail.com

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 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!

I have had Thunderbird on my Mac Monterey synced to my Comcast email address with no problems. Usually I have to enter my Comcast password when I send the first message for the day. It has caused no real problems since I obtained this computer, probably sometime in 2021. Within 2023 I obtained a Windows 10, onto which I also put Thunderbird. Last November I upgraded to Windows 11 had kept Thunderbird. I did not do the upgrade myself. The technician used Google Drive and OneDrive for backup. I added a GMAIL address on that system to my Thunderbird installation on Windows 11.

For the past week Thunderbird has been popping up a Comcast site requesting that I enter my Comcast password. This is bizarre! How can I get my Thunderbird to behave more normally on my Windows 11? Thanks in advance. The technician only did the upgrade. I did the subsequent program reinstallations.

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

Using Thunderbird 115.18.0esr Supernova 64-bit on Mac laptop OS 10.13.6. Worked fine for years, with ongoing Thunderbird updates, even though Mac OS is 32-bit. Suddenly, after 10/6/26 can't retrieve emails although I can see them on the ATT Yahoo server website. Can still send emails with Thunderbird. Inbound server settings are: POP server inbound.att.net, Port 995, SSL/TLS, Normal Password (I long ago created a Secure Mail Key, and even tried creating a new one). But inbound server name doesn't show in Saved Passwords (only outbound server with Secure Mail Key as password)? I have tried everything suggested, repaired my inbox folder, updated Thunderbird files, etc. in Profile as recommended. But still no prompt for password when attempting to get messages. Just shows "Done" at bottom left with no new messages received. But new messages are seen on server website. So it appears that Thunderbird isn't able to connect to the ATT Yahoo server to get emails. Why? And what else can I do? I love Thunderbird and want to continue using it.

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.

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

My inbox is not updating for my personal or work account. I recently reset the password for my company account and since then I have not received new emails on thunderbird.

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.