Thunderbird: Free Your InboxJan 5, 2023

PSA: We're aware of an issue affecting #Thunderbird users using #IMAP to connect to certain #Microsoft account servers (for example: outlook.office365.com).

These users are receiving an error message that says "User is authenticated but not connected."

We believe this is caused by Microsoft running certain services with broken #IPv6 functionality.

WORKAROUND: Disable IPv6 networking in Thunderbird's advanced config.

MORE INFO: https://answers.microsoft.com/en-us/outlook_com/forum/all/thunderbird-imap-responded-user-is-authenticated/062a82f6-e678-4462-88b7-dd6cc318386f?page=1

Redirecting

Show threadPadraig 🌈Jan 5, 2023

@thunderbird it could also be that Basic Authentication (IMAP and POP) is being turned off for everyone this week!

Modern Authentication is required which doesn't work natively on TB

Show threadNathan Phillip Brink (binki)
@padraig @thunderbird But… we have been forced to use OAuth2 for months already and it was working great, even over IPv6, prior to Microsoft breaking things on 2022-12-26 or 2022-12-27. I do not think this is related. It is some Microsoft internal thing whose details we will never hear about. My theory is that ratelimiting and CIDR techniques that work with IPv6 don’t work with IPv4 (since Microsoft has used this error message in the past when you are being ratelimited).
Jan 5, 2023 at 5:19pmWeb