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
    2022-12-29T00:05:44+00:00

    Hi Ankur,

    Thanks for your post with pictures, I have checked it and our settings are exactly as posted. I am 100% positve that some sort of bug is currently causing this issue.

    Hello, Mr. Glenn, as said by other colleagues before, by disabling IPv6 from Windows Network, it get working for me again, after restart Thunderbird.

    Other colleague said the by disabled ipv6 netwotking in thunderbird advanced configuration editor (network.dns.disableIPv6 = true), worked for him, but I did not try to do that.

    Hope been helpful to all

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  2. 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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  3. Anonymous
    2022-12-28T13:53:34+00:00

    same here. last successful fetch of any messages via imap was yesterday december 27 around 21:00 utc. also using thunderbird. also at a university. also accessing via outlook.office365.com using oauth2. have deleted the oauth entry in thunderbird's saved passwords and reauthenticated. have restarted thunderbird. have switched to basic auth and then back to oauth2 in case that would clear things. have tried using imap-mail.outlook.com instead with no joy. consistently getting this notification message from thunderbird:

    "The current command did not succeed. The mail server for account HWU responded: User is authenticated but not connected."

    followed by this notification message from thunderbird:

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

    i have no problem accessing my mail via firefox via https://outlook.office.com/mail/inbox.  as far as i know, i am using my correct primary mail address. i am unaware of any alias. outgoing email via smtp.office365.com using oauth2 works fine.

    where can i get more information about this?

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