Hello,
I have several existing users in Active Directory with an @ symbol in their username. For example, te@stuser and testuser@. When authenticating to AD FS, the tes@studer can authenticate fine with their UPN (with te@stuser@example.local) but the testuser@ user (UPN of testuser@@example.local) cannot. This user gets pulled up on the input validation at sign-in, stating Enter your user ID in the format "domain\user" or "user@domain". I have tried both example.local\testuser@ and testuser@@example.local with the same result. The username is in the correct format of user@domain, it just has a trailing '@' symbol on the user part.
How can I best overcome this problem?
Thanks.