@jeffduke
Yea that reply from MS is incorrect. We have thousands of customers using all different types of mail providers and SMTP servers (cloud and self-hosted). I have O365 and Google configured and working as we speak.
Maybe the person from MS meant your O365 account is forced to use the new OAuth method and we only support basic authentication at the moment? If that’s the case then we are releasing OAuth2.0 support soon. If 2FA is the issue then all you have to do is create an app password and use that in place of the password in osTicket.
In any regard, MS should’ve provided you with a more educated, detailed reply rather than just “the software isn’t compatible”.
Cheers.