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
    2022-12-31T19:03:16+00:00

    I do not know whether this helps:

    at the University my mail reader (any of them) works

    without changes, and at home it fails even if I disable ipv6.

    Either at home or work I can read my email from Firefox if I go

    through my tenant Office365: correio.pucrs.br

    but when I log out I cannot log in again using https://login.microsoftonline.com/common/oauth2/login

    Login works only from the tenant Office365.

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  2. Anonymous
    2022-12-31T19:58:44+00:00

    Do we have any theories as to why some end users would see this and some not? e.g. is it to do with their particular service provider? (accepting the root cause is likely something Microsoft have done).

    It is most likely that your users are using IPv4-only networks or are using recursive DNS resolvers which do not return IPv6 records or prefer IPv4. More and more people are using turnkey internet access solutions from ISPs which support IPv6, but I suppose there are a lot of people out there still using outdated infrastructure who would not notice this problem. If the people who did not report the problem are only accessing Office365 while at work, maybe you are in a position to check whether or not your own infrastructure doesn’t support IPv6 yet ;-).

    My phone which connects to Office365 using IMAP (using K-9) got a few mails yesterday when I was driving somewhere. It probably ended up on a network which doesn’t support IPv6 or managed to configure its IPv4 but not IPv6 temporarily while I was out and that would explain why it managed to grab a few mails since it hasn’t been able to sync due to this issue either.

    My tenant is charity related so users are all volunteers accessing from their own home. I've had a dig around and my own provider (PlusNet in the UK) seem to have been dragging their heels on IPV6 rollout for some years now, and I'm seeing no indication it is fully resolved yet - so that might explain why I don't have the problem.

    My affected user has worked around the problem with the IPv4 config tweak.

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  3. Anonymous
    2023-01-02T09:46:10+00:00

    Fellow mutt user here, with offlineimap.

    I have the same problem. I fixed it by adding "ipv6 = False" under the [Repository RemoteMyUnivO365Account] section in ~/.offlineimaprc.

    Thanks all for the help!

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