Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
I've done a little more digging, and here's what I've discovered...
- 123 Reg is part of GoDaddy
- These two companies have an arrangement with Microsoft to be able to sell their own versions of Microsoft 365.
- Their packages have limitations or restrictions in comparison with the standard Microsoft offerings, but this enables them to undercut the prices that Microsoft is charging.
- It seems that in migrating to a new Microsoft 365 platform, 123 Reg has joined GoDaddy in federating Microsoft 365 with its own authentication system (?) This means that when you want to sign-in to Microsoft 365 you are presented with a 123 Reg login screen and not the normal Microsoft login. (Which might explain why things were no longer getting as far as going to Microsoft Authenticator???) It is at this point -i.e. signing-in via 123 Reg's login page - that I experience the AADSTS50107 error, and can get no further.
- So, the issue, as well as any likely resolution if 123 Reg is not able to fix the problem any time soon, seems to revolve around Federation.
- As for options, I guess we can wait for 123 Reg in the hope that they and Microsoft can fix this, or we could request that they defederate our Microsoft 365 and help us to move to Microsoft, or we could seek expert IT assistance to do that for us.
- From the posts of others who have been impacted that I find online, it would appear that 123 Reg's migration of Microsoft 365 to a new platform has created quite a mess and serious disruption for many users!