This article covers common problems regarding Azure AD SSO.
Trouble signing in
Sometimes users will be unable to sign in if the user was not assigned to the application.
Amend this by assigning the user to the application.
Invalid user attributes
There are times when attributes submitted by a user does not match the ones in Azure AD. When that happens, users receive an error message.
This can be amended by determining what was entered that was mismatched, typically the email address has changed, and update that user’s profile information to match.