Instructions on how to configure Thunderbird to work with Office 365. Images depict Thunderbird on macOS, but the steps will look similar for Thunderbird on Linux or Windows.
As of October 12, 2022
If you are already using Thunderbird, you may need to remove your account then re-add it.
UT O365 accounts now use Modern Authentication, also called OAuth2. How email clients handle this authentication differs from the previously used Basic Authentication which has officially been discontinued.
To remove an account from Thunderbird:
To add your account again, quit and reopen Thunderbird then follow the directions below.
Thunderbird is not an officially supported email client
We strongly recommend switching to the Outlook Desktop app or the Outlook Web App
Microsoft does not support Thunderbird for use with O365 accounts which often results in significant limitations of functionality. We cannot guarantee that UT O365 accounts will work and can only provide best effort support.
Thunderbird is also a third party application and is blocked by UT O365 by default— while an exception has been granted allowing for its use with UT O365 accounts, the exception could be revoked at anytime without warning if sufficient cause is identified.
Thunderbird is now configured for use with your UT O365 email.