Thunderbird IMAP responded: User is authenticated but not connected

Anonymous
2022-12-27T12:29:12+00:00

Since yesterday, my Thunderbird client cannot connect to the outlook.office365.com IMAP server and other users at my university are also having this problem. I have deleted the stored token and redone the connection procedure but it does not work. I get two error messages:

The current operation on 'inbox' did not succeed. The mail server for account ... (IMAP) responded: User is authenticated but not connected.

Server outlook.office365.com has disconnected. The server may have gone down or there may be a network problem.

This does not work on any platform: Windows, Linux or Macos. Via the browser, we can access the emails but it is a workaround because it does not support openPGP. We need Thunderbird

Outlook | Web | Outlook.com | Account management, security, and privacy

Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.

0 comments
Answer accepted by question author
Anonymous
2022-12-28T22:03:29+00:00

Hi Glenn,

Which version of Thunderbird are you using.

I have 102.6.1 which is the latest one. Can you try updating it if its not and then check.

Also under Thunderbird --> Click on the gear icon on the bottom left bar --> General --> Config Editor --> Show All

Type network.dns.dis in the search field

Select the very first option and click on the toggle arrow on the right, make it true

Close and reopen Thunderbird.. See if this helps

Let me know how it goes

Was this answer helpful?

300+ people found this answer helpful.
0 comments
Answer accepted by question author
Anonymous
2022-12-28T21:34:14+00:00

Yes, it is worked for me too!

I just disabled ipv6 netwotking in thunderbird advanced configuration editor (network.dns.disableIPv6 = true)

and it is works again like a charm!

Was this answer helpful?

100+ people found this answer helpful.
0 comments

131 additional answers

Sort by: Newest
Most helpful Newest Oldest
  1. Anonymous
    2023-01-05T07:05:22+00:00

    Thanks for notification of the update / fix on the Microsoft side. Just reverted network.dns.disableIPv6 back to false, and I am not receiving the original error. email seems to be working normally.

    Was this answer helpful?

    2 people found this answer helpful.
    0 comments
  2. Anonymous
    2023-01-05T04:53:31+00:00

    It looks like Microsoft just fixed it in the last few hours! Yay!

    Was this answer helpful?

    6 people found this answer helpful.
    0 comments
  3. Anonymous
    2023-01-05T02:38:03+00:00
    • I upgraded from Windows 10 to Windows 11 on December 15, 2022
    • Thunderbird was updated from 102.6.0 to 102.6.1 on December 21, 2022.

    These points are unrelated to the issue.

    Is there any other information that can be helpful in determining the root cause, so the root cause can be fixed?

    Microsoft already has enough information to investigate the root cause. But since they operate and develop the system which is broken, they are the only ones who can actually investigate the root cause. We're all waiting to hear from Microsoft on this issue.

    Thanks again all tenant administrators who have raised tickets.

    Was this answer helpful?

    1 person found this answer helpful.
    0 comments