Can't log-in anymore via Microsoft 365

We’ve started using Anaconda Notebooks to teach Python to our undergraduate Engineers, and at the start of the semester a few weeks ago they were all able to log-in via their Microsoft 365 accounts with the University via SSO. This feature seems to have been silently removed, and some are now unable to log-in at all to their original accounts. Is there any way to access these accounts that now say “Email already in use”? Why has the Microsoft 365 login been removed? I assumed from the latest T&Cs that Anaconda expect us to still use their offerings for our teaching curriculum - but this appears to be an active move to discourage it…