You mention Teams invitations, I would say that if you're using 365 for corporate email then they'll start disabling basic authentication in a couple weeks, so as much as I hate to say it, you might need to use Outlook. I know our company is disabling access from all other email programs.
-x16wda
This might explain why I can no longer authenticate my Office 365 e-mail account via the BlueMail app. I keep getting a "Network unavailable" error, which does not make sense. Out of frustration I went ahead and installed the Outlook app, and found that the exact same login credentials worked flawlessly on the first try.
Fortunately, I remembered seeing this forum thread just recently, and opened it to see if anyone chimed in with recommendations for the original poster.
This is disappointing. It was very useful to have all my e-mail accounts available in one app (BlueMail). This is yet another example of further Balknanization of the Internet. We deserve so much better.