Disable account hub in Settings/General, try again from ⩸ - New Account - Email.

Disable a VPN if in use.

Brian, what were your results?

Sorry, on re-reading, I was not clear about the result.

The result was I was unable to add the <name>@outlook.com email address to Thunderbird using version 143.0.1 on Windows 11.

There was no VPN in use either during my attempt or my friend's attempt (which was using Windows 10).

My friend's attempt failed in a way that indicated some partial corruption in that the new email address was added but it failed to create the folders within Thunderbird.

NEW RESULT following account hub disablement suggestion: I've just tried it again following the above suggestion from SFHowes to disable the new experimental account hub and it appears to have worked perfectly. (Note that it worked using version 140 (esr) mentioned above without disabling the account hub).

Many Thanks and regards Brian

I spoke too soon.

The addition of the outlook.com email address was successful.

However, attempting to send an email from thunderbird failed with the message

   "Login to server smtp-mail.outlook.com with username <name>@outlook.com failed"

There was a button with an option to update the password but pressing it did not bring up an option to do so.

Sorry, that's all I have time for now. It appears the default settings for the outlook servers is not entirely satisfactory.

Just one additional point to make here is that the esr version (140.3.0) also fails to send emails with the same problem. 140.3.0 is configured to 'Create accounts in the new account hub'.

Version 143.0.1 is configured with the new account hub option unchecked.

Both versions are behaving the same but outlook is not happy with the configuration of the outgoing server.

Regards Brian

If the account is already in TB, use these settings:

incoming IMAP server: outlook.office365.com, 993, SSL/TLS, OAuth2 authentication, User Name = email address

outgoing SMTP server: smtp.office365.com, 587, STARTTLS, OAuth2 authentication, User Name = email address

Accept cookies in TB (not browser) Settings for OAuth2 to complete.

Many Thanks, SFHowes.

That's the detail I was missing.

I removed "-mail" from the value provided by the automated setup. I can confirm that this makes both versions work correctly.

As I understand it, there is a mozilla database which provides the incorrect value for the Outgoing server.

Am I right to assume that the mozilla default values wil be changed, or is there some circumstance that the smtp-mail.outlook.com value is correct?

The database refers to smtp-mail.outlook.com, which is odd because smtp.office365.com has been correct for years, even though MS suggests the other name. It's all a mystery to me.