Read this answer in context 👍 0 All Replies (2) A confusing time indeed, but that's what you get for using microsloth. :PĪpp passwords is also a PITA to find, so here's a screenshot: Almost immediately, a half day's worth of e-mail plopped into my inbox.ĭespite receiving the connectivity errors with the initial app password, my e-mails would still be sent, I just couldn't receive anything. Finally, I created a second app password and applied it to my account. Following the attempt to use my app password in TB, I changed my O-365 password entirely and updated TB. As near as I can tell, this 'default' app password is not actually functional. Naively, I thought that would work with ThunderBird. When I setup MFA with O-365, it created an app password as part of the process. I was able to finally resolve the issue by basically turning it off and turning it back on.

TL DR - Don't use the initial app password, create a new and unique app password for every app.

You are correct, app password must be completely unique.

Thunderbird office 365 configuration