sudha
I don’t know then. The only thing I can think of is the token was retrieved with the wrong account. If all else fails consult your mail logs and authentication logs in MS to see what’s going on. Make sure it’s using the proper email address when authenticating, etc.
You can also try completely deleting the emails in osTicket and recreating them. Maybe something in the database is causing them to hang onto old credentials, etc.
Cheers.