Thunderbird Community Forum

All of the incoming messages are going to Trash. This includes messages I have not indicated as trash. I get no new messages to my inbox. Started today, 09/04/2026.

As of September 3, 2026 all my new emails are going into a random folder instead of the inbox. This is also happening on my wife's PC plus and we are not getting the emails to our iPhones until we get out of Thunderbird. What has changed? This has not happened before.

After fixing the view problem of my email in Thunderbird (thanks for the F8 tip!), my email stopped downloading. I have no "prompt for password" checked. There isn't a primary password checked. I've confirmed the pop outgoing email is correct with the email provider (google). I can get into it without any issues and see my emails there.

I've re-entered the password for the pop outgoing email to no avail.

Since the last (v155) update, TBird started putting all incoming email into one subfolder under my main inbox. I have several message filters that sort incoming mail into various folders. When I disabled the message filter associated with the folder in question, the email started coming into my inbox folder again. The message filter connected to that folder has not been changed in a while, and is a "match any of the following" rule with a number of specific from/contains/[text] entries. When I examined the filter closely, I found two rules where the [text] field was blank, which apparently was causing the problem, but as I said, I haven't changed the filter in a while - what recent change might have caused this? (Either adding empty fields or else considering [blank] to be equivalent to [any].)

Thunderbird has stopped getting messages and 'get messages' doesn't work & I have to close & restart thunderbird to receive them. Nothing has changed with the email client itself.

I know messages have arrived by checking my providers phone app, but for Thunderbird to download them to my PC I now have to restart Thunderbird to get new messages

Thunderbird demands my password for outgoing SMT server when I go to send an email but when I enter it, system won't accept it even though it is the correct password. I have had this problem for some time and it comes and goes. Sometimes I have ebeen able to send without a problem, then it comes back I had a helpful reply from this forum (can't find who posted it - Mick?) tellling me to go into the error console (Ctrl + Shift + J) and delete eveything in that. I tried that. It worked at first, but now when I do it, it has no effect. And the problem now appears to have become permanent, although occasionally after I have been working for some hours, then suddenly I can send without any problem. Problem hasn't budged though for a couple of days now. This is a mysterious and erratic gremlin, which now seems to have taken root. Any suggestions please? Carol

When I send an email with my HTML file signature Thunderbird appends a text signature as well. The text signature is not visible in the draft email, and is not in the settings. The text signature is added for separate identity with no signature enabled. I want to stop this. Any ideas please?

Hello,

Recently, the manual message check feature has stopped working, whether I use the “Get Messages” button or the menu.

When this feature was still working, I could see the progress of the message retrieval from the server in the status bar; now nothing happens (no display in the status bar and no messages are retrieved).

I should note that this isn’t a connection issue, since new messages are successfully retrieved during periodic checks or when Thunderbird starts up.

Has anyone else encountered this problem?

Thanks!

I am unable to send Email. I am using THUNDERBIRD app..My Email address is ronniekeys@talktalk.net. I am receiving mail but cannot send.. I have a message that reactivation is required after being blocked. [ have paid my subscription but still blocked. Thunderbird version 155.0

Outlook.jpの個人アカウントをThunderbirdで使用しています。 IMAPは outlook.office365.com / 993 / SSL/TLS / OAuth2 で正常に受信できます。

SMTPは smtp-mail.outlook.com / 587 / STARTTLS / OAuth2 で送信すると、 535 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox. と返されます。

smtp.office365.com / 587 / STARTTLS / OAuth2 も試しましたが、こちらは接続タイムアウトになりました。 MicrosoftアカウントのOAuth2認証と2段階認証は完了しています。 Outlook Web版・新しいOutlookでは送受信正常です。 Microsoftサポートには問い合わせましたが、Thunderbird側へ確認するよう案内されました。

この状態でThunderbird側にまだ確認すべき設定がありますか？ それともMicrosoft側でSMTP AUTHが無効になっている状態でしょうか？

This started almost two months ago. When I open my email on Thunderbird, the inbox fills OK. As I go through the emails at some point, several just disappear from Thunderbird? When I access my emails directly from Spectrum, they are still there, but if I refresh they may disappear.

I paid an expert on Just Answers and he spent over an hour and came back with Spectrum was having issues, they were aware and they were fixing them. I thought the problem was solved, but then it kept on happening. I am losing important documents every day! Please help me!

All of a sudden, all of my incoming messages in Thunderbird are getting sent to "Local Folders/Trash" I have made NO CHANGES to the account nor did I set up any filters. When I try to manually move messages I want from trash to the inbox, it automatically sends them back to the trash folder.

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 a recurring problem with Thunderbird 153.2.0esr (64-bit).

After clicking the Send button, the message is successfully sent to the recipients. I can see that the sending process takes place, and I have confirmed that the message was actually delivered because I was one of the recipients myself and several BCC recipients have replied to it.

However, after sending, the message sometimes does not appear in the Sent folder. Instead, it remains in the Drafts folder.

This is particularly problematic because it gives the impression that the message may not have been sent, although it actually has been delivered. There is therefore a risk of sending the same message again by mistake.

The problem occurs only occasionally. The most recent occurrence involved an email sent to approximately 180 recipients via BCC with an attachment of about 1.8 MB.

My email provider is WEB.DE and the account is configured as an IMAP account.

In Thunderbird under Account Settings → Copies & Folders, the option to save a copy of sent messages in the Sent folder is enabled.

Expected behavior: After successful sending, the message should be removed from Drafts and a copy should be stored in the Sent folder.

Actual behavior: The message is successfully sent, but remains in Drafts and no copy appears in the Sent folder.

.I get this meassage when I try to send an email from my thunderbird account - Sending of the message failed An error occurred while sending mail. The mail server responded: This account has been disabled due to suspicious activity.. Please verify that your email address is correct in your account settings and try again.