Are you having problems signing into Microsoft Teams? We have had a number of calls from clients that are having this issue.
Its a known issue at Microsoft and we have a simple fix for it.
The reason why this is happening is because you have a personal Microsoft account linked to your Microsoft365 business email address. You can tell if this is the case if you get the below message when signing in, asking you which account you would like to sign in with. This is never a good idea to have in any case but this seems to be causing quite a few errors. Once you have changed the email address or removed this other account (making sure you have no data or other services linked to it) this fixes the issue.