* https://blog.thunderbird.net/2023/01/important-message-for-microsoft-office-365-enterprise-users/ https://blog.thunderbird.net/2023/01/important-message-for-m

* https://blog.thunderbird.net/2023/01/important-message-for-microsoft-office-365-enterprise-users/ https://blog.thunderbird.net/2023/01/important-message-for-m... * https://office365.mcmaster.ca/reconfigure-mozilla-thunderbird-for-modern-authentication/ https://office365.mcmaster.ca/reconfigure-mozilla-thunderbir... If you've constantly upgraded over the years, try creating a new account or even reseting your profile. Perhaps there are/were some 'stale' settings that are messing things up.