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

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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
    2023-01-04T12:38:27+00:00

    Ich habe ein deutschsprachigen Thunderbird und kann in der Suche die Einstellung für network.dns.dis nicht finden.
    Können Sie mir helfen??

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  2. Anonymous
    2023-01-04T09:37:57+00:00

    It works for me, BIG Thank you AnkurSrivastava_3010

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  3. Anonymous
    2023-01-03T19:32:44+00:00

    This is really about v4 vs v6 and not about thunderbird at all. On Linux i added a bunch of the v4 IPs of outlook.office365.com to /etc/hosts that magically repaired both thunderbird and claws-mail, no matter the version, no matter the oauth client_id i would use.

    IMAP over v4 works, over v6 it does not. Not sure if davmail would have been able to talk its stuff over v6, or whether SMTP would have worked.

    I suggest Microsoft improves their infra testing a tiny bit, how can such a thing slip and not be fixed for a week or more.

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