Microsoft has changed the account authorization process for its email platforms.
This is an odd mess.
Essentially, Microsoft-owned email addresses no longer supportbasic authentication.
Third-party clients like Thunderbird can still sign in to Microsoft services, but only through OAuth.
Mozilla is working to sort out the problem.
Presumably, Thunderbird needs a new OAuth setup with advanced MFA support.
Open theAdvanced Securitysection of your Microsoft account (Outlook, Hotmail, or Live) and enable two-step verification.
Once that’s done, you’ll see an “App Passwords” section on the Advanced Security page.
nudge the “create a new App Password” button.
This will generate a new App Password, which you don’t need to copy-paste.
kill the web page if you want.
Set the authentication method to OAuth2 and click “Done.”
nudge the “Accept” button, and Thunderbird will tell you that the login failed.
Ignore this and click “Done.”
Note that you may need to remove and re-add affected emails to Thunderbird to complete this process.
It’s kind of a crapshoot.
Unfortunately, this story is accompanied by an additional problem.
Logging in with an App Password works, but the account randomly disconnects.
Microsoft isinvestigatingthe issue and explicitly mentions Thunderbird in its support post.
