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.

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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

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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!

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  1. Anonymous
    2022-12-28T20:33:43+00:00

    My issue solved by disabling IPv6 from windows network.

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  2. Anonymous
    2022-12-29T18:08:26+00:00

    It's true that we don't know who is to blame yet.

    Meanwhile, here is an alternative workaround with less side effects:

    network.dns.ipv4OnlyDomains = office365.com

    See http://kb.mozillazine.org/Network.dns.ipv4OnlyDomains

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  3. Anonymous
    2022-12-28T21:55:48+00:00

    I was unable to change my config so that it wouldn't do ipv6, however I changed my config so that it would point to 52.98.152.178 (ipv4 address of outlook.office365.com) and everything works without a flaw. For me this confirms that the issue is with Microsoft 100% and that I didn't get any reply whatsoever on my ticket until now dissapoints me a great deal.

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