Hi,
Please refer to the following document to check if the account has been configured correctly:
http://support.veritas.com/docs/249456
How to configure a Microsoft Exchange 5.5 and 2000 individual mailbox backup for Backup Exec 8.x, 9.x or 10.x software
Hope it helps!
NOTE : If we do not receive your reply within two business days, this post would be marked ‘assumed answered’ and would be moved to ‘answered questions’ pool.