I-Thunderbird Community Forum

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!

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

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 have been receiving the error message quoting the SCO1 policy about reaching my sending limit every day recently. This has happened even when I have only sent 1 or 2 messages and these have only been to a handful of people.

"Sending of the message failed. The message was not sent due to exceeding the allowed number of recipients. The server responded: Policy-SC01 You’ve reached your sending limit. Don’t worry, you can send again soon.."

I have seen a previous strand where this was explained as being something imposed by the email provider not Thunderbird. However I have managed to send emails from the website of my email provider that I haven't been able to send through Thunderbird. This suggests that the previous answer was wrong. I would like to use Thunderbird so please help me sort this out.

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

I have three separate Yahoo email accounts. I set up Thunderbird to link to each Yahoo email account separately. It worked fine for a year or more. On 5/25/26 one of the three Thunderbird email accounts stopped downloading emails from Yahoo. I could see at the bottom bar Thunderbird indicating that is was downloading 1 of XX emails, but never actually downloads them. There is no error message. I checked the Yahoo email account to verify the number of emails I am missing from Thunderbird and the number is correct. I can see the emails in Yahoo. I'm the only person using Thunderbird, so no changes have been made to previous settings for retrieval. I confirmed Security and server settings for Thunderbird in and out going emails, and Yahoo are correct. I tested the connection in Thunderbird, and the connection is successful. I tried to send an email from the Thunderbird account having issues, and the email was sent and received by the recipient. The recipient replied, and Yahoo received the email, but failed to download it to Thunderbird...along with all the other emails since 5/25/26. I unlinked the account and reestablished the link between Yahoo and Thunderbird, and still not fixed. I tried restarting the computer, with no change. I tried to send an email from Thunderbird to one of the other Thunderbird emails and it was sent and received. I made changes to Thunderbird to force the download of emails, and it still wouldn't do it. I turned off my antivirus, closed Thunderbird, and restarted it, and that didn't change anything. The capacity of emails on the email in question only has 739 emails, so it's not over the limit and I have plenty of storage capacity. Thunderbird is set to save emails, Cookies and cache were cleared, no change. I ran the folder repair feature in Thunderbird, but there was no change. I compared all the settings between the other Thunderbird emails that are working against the one that isn't, and they are all the same. There was a suggestion to close out of Thunderbird and delete the "Global-message-db.sqite" file from the Thunderbird profile in case it was corrupted, and it would recreate this file when Thunderbird was restarted. The file was recreated, but it didn't fix the problem. There was mention that a suspicious email in Yahoo might be blocked by Thunderbird, so I placed various emails in the spam folder, and it didn't work. I did find one email in the Yahoo spam folder that was dated before 5/25/26 and moved it to the Yahoo inbox. Lo and behold, that one email downloaded to Thunderbird. So there is something within Thunderbird preventing emails from downloading after 5/25/26. I've read many people complain about similar download failures with no solid fix. Someone mentioned it fixed itself on a day, but then stopped again days later. Someone else mentioned Yahoo changed its password protocol to transfer emails, but that doesn't make sense since the other two are still downloading based on the "old" password protocol. I'm at wits' end. Thanks for reading all of this. I hope someone has a solution.

Hello,

Everything working just fine last night. Wake up and Thunderbird will not retrieve emails.

Remembered this old message I got so I went through and deleted my second email address, didn't help.

https://support.mozilla.org/en-US/kb/thunderbird-and-yahoo

Checked all settings compared to Yahoo, still won't download messages. I can even send a message with my current settings no problem, and it does login, just won't retrieve emails. Gives me a connection timeout.

Anyone have any ideas?

After returning from a 6 day vacation, my wife attempted to download email from her Yahoo email account. There are nearly 200 messages that have piled up but they aren't moving. I've uninstalled and re-installed TB. I've uninstalled and reinstalled the app password in Yahoo. There is no problem with accessing the email via any web browser. I spent 49 minutes on a tech support call with Yahoo and they have said the problem is with TB because they repeated the same steps I have. I checked firewall settings and the only antivirus program on the computer is Malware Bytes and it's not running in the background.

The version of TB is the most recent as of yesterday. I don't see any sketchy looking emails in the web version of Yahoo Mail when it's opened. It's set up as a POP3 account and has been since Cox Internet gave their email over to Yahoo. I'd appreciate any assistance in resolving this because it's currently above my pay grade and tech support at Yahoo.

I can send emails but I cannot receive them. I can receive them at Spectrum.net. The problem started the evening of the 26th. Everything was fine during the day. But in the evening I could no longer get email. I am not aware of making any changes to either Thunderbird or to Spectrum. I did call Spectrum but they could not find any problem on their end. I recently changed the password in Spectrum but Thunderbird has the updated password. All of the settings in Thunderbird look right. Any ideas on what I should do?

"connection to server pop.mail.yahoo.com timed out" I have been getting this message in the activity manager for about a week now. When I click get messages, it says down loading message 1 of 1, but nothing happens.

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.

After latest update Thunderbird cant send or receive emails. My settings are correct mail.charter.net port 993 outgoing mail.charter.net port 587.

Tells me I have a server error and is constantly asking for my password. HELP!!! I have been with Thunderbird since the beginning and have sent money to the cause, and now I need your help.

Thanks, Pam

This isn't a crash, but it's an error that keeps happening as I'm typing my email. It's a problem with saving drafts. The error message reads : Error while saving draft. The configured key id "0x8DC635DD33C6A871" cannot be found on your keyring.

I can't type an email longer than say 30 seconds without this error constantly coming up until I send the email. (Needless to say I also can't save to drafts)

Uninstalled and reinstalled Thunderbird and same problem.

My computer was wiped and I imported my last profile when installing Thunderbird.

Would not want to lose all my email in order to start a fresh profile :(

Also, as I was went looking for the version of Thunderbird I noticed it seems to be having trouble doing an update. I'm using the release update channel.

Been using Thunderbird for 25 years and never had this issue before.

I have a filter setup to forward certain emails to another account. It has been working fine for years. Suddenly today I am getting an error message about not being able to contact the smtp server. If I manually forward the email to that same address it goes fine.

Every time I send a message, it duplicates itself. Any help in removing this problem in the settings will be appreciated. Please keep in mind I'm not that savvy with settings so if you can keep this simple like me, that would be great. I'm using version 151.0 64-bit on Windows 10. Hopefully someone be able to help me resolve this problem.

Thank you, Joe

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.

Hi, I'm using Thunderbird for Yahoo Emails since many years (it's great!).

In March/April 2026 I changed the Server Settings (authent. method) to OAuth2, it has worked properly.

But since 23.9.2026 I cannot receive Emails in Thunderbird any more (only for the Yahoo account, I have another Email Account working properly in Thunderbird). Bottom text is "Message 1 of 33 will be downloaded", but nothing is downloaded after severals minutes.

My Yahoo Account in the Firefox Browser works properly, its ONLY Thunderbird (and probably OAuth2?). I have removed my Oauth2 Password in saved password of Thunderbird and generated a new one, but that does not help.

So if this issue cannot be solved, I will use another Email Program instead of Thunderbird!

Kind regards Soenke