I have confirmed with the latest version my non windows system now uses 1.2 instead of v1 TLS, which means that if that was the cause of your problem, it should now be fixed.
20.9.66 works around the previous buggy .Net implementation of security.
If you have a problem now, it is obviously going to not be related to TLS specifically and will instead relate to either your credentials or a certificate issue.
In either case, whether it works or doesn’t, it would really help if you report your findings after testing the latest version.
That makes a lot of sense. Because you were having the issue in windows as well, I was more confident yours was the authentication issue that others exoerienced.
App Passwords are slowly dying and many platforms are getting rid of them in place of other options and 2FA.
I think you may have mentioned and tried this (but it’s hard to go back and check when you’re replying on a mobile device), I do believe if you had of used your actual/real main account mail settings, that is a work around for the MFA problem as the users real account is treated differently to the app password model. I’m sure others have reported success there before.
Thanks for providing the screenshot, that’s good that Microsoft have acknowledged the issue that server settings sometimes overwrite certain user settings.
