2009754 - Bizarre bug in Thunderbird (Linux version) – either a long delay or an smtp timeout occurs when trying to send emails through smtp.outlook.com until you click on any email folder inside the main window

Status: RESOLVED DUPLICATE of bug 1993576

(MailNews Core :: Networking: SMTP, defect)

Description

[seven]

Attachment: smtp settings

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:146.0) Gecko/20100101 Firefox/146.0

Steps to reproduce:

There is a bug that occurs when attempting to send an email through outlook/hotmail (using the smtp.outlook.com server with port 587 STARTTLS Oauth2) that either results in a time-out or it takes a very long time to send. Even if it’s just a test email with no attachments. After you click on “Send” from the new email window, a small window popup is displayed and says “sending” but sometimes nothing happens and eventually you’ll get a timeout like this:

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

Actual results:

The absolutely bizarre solution to this problem -before a time out occurs- is to click on the main Thunderbird window and then click on any folder under an email account (such as inbox, sent items, any custom folders etc…) that is not currently selected or active (e.g. if inbox is currently selected in the main window then click on the sent items folder or vice versa) and after that the new email window will close and the email will be sent immediately. This works 100% of the time.

If you try sending a large file as an attachment e.g. 10MB it will not begin uploading any data (as can be verified through the system monitor) until you click on an email account folder as described above.

Note that this only happens under Linux and not with the Windows version of Thunderbird. After sending more than a 100 test emails trying to figure out what the cause was and changing different recommended settings I accidentally found this to be the solution as detailed above (as strange as it sounds) and I am able to reproduce it every time.

What’s even more bizarre is that this bug doesn’t happen with my gmail account, only with my Microsoft accounts.

Expected results:

The email should send immediately without a long wait and without timing out.

I am completely baffled as to why clicking on any email folder inside the main Thunderbird window causes the email to be sent almost immediately even if it was originally taking a long time to send. This works every time and it doesn't time out.

System details:
Thunderbird version: 145.0
Operating System: Manjaro Linux (Arch based)
KDE Plasma Version: 6.5.4
KDE Frameworks Version: 6.21.0
Qt Version: 6.10.1
Kernel Version: 6.18.3-2-MANJARO (64-bit)
Graphics Platform: Wayland

Notes:

• I tried starting Thunderbird in troubleshooting mode (plugins are disabled) and the result is still the same
• I tried creating a new profile in Thunderbird
• I tried using a different internet connection
• I tried this on two different Linux systems (laptop and desktop)
• Sending the very first email after opening Thunderbird after a reboot or restarting Thunderbird is usually immediately successful
• Thunderbird on Windows does not have this issue
• I do not have an active virus scanner so there is no interference from any antivirus software
• I tried turning off the firewall completely and restarting Thunderbird but the result is the same
• I tried deleting the saved passwords and re-logging into my accounts but nothing changed

Comment 1

[seven]

@Corey Bryant

Yes this seems to be the same!

Specifically this comment! https://bugzilla.mozilla.org/show_bug.cgi?id=1993576#c12

This is exactly what happened with me and it took me almost a week for to figure it out because it seemed so random! What a strange bug! 😭