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
    2022-12-28T21:36:01+00:00

    Hi Joe,

    This happened off lately.

    In order to check for security defaults. You can go to Azure Portal.

    From there Azure Active Directory --> Properties as shown

    From here you would be able to see if it is enabled or not.

    If enabled turn it off.

    Secondly if you have Azure Conditional Access enabled for MFA for all users that could be also a issue since Azure Conditional Access blocks access to legacy apps which support SMTP authentication.

    Also in the Admin Centre check for the snippet below

    See if this helps.

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  2. Anonymous
    2022-12-28T21:27:07+00:00

    We are having the same issue, it's very problematic for us, we are using oauth 2.0 so not legacy authentication, not sure what we can do to get this fixed.

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  3. Anonymous
    2022-12-28T20:56:48+00:00

    dear AnkurSrivastava,

    where is this switch to "modern authentication" documented? if you are referring to the switch to oauth2, thunderbird supports that (one of the very few (if not the only) libre mail apps that makes this work with outlook.office365.com).

    i've been able to use mfa authentication with thunderbird to connect to outlook.office365.com since i switched to thunderbird 15 months ago when my organization turned on mfa authentication for nearly everything including email.

    best wishes,

    joe

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