The email is generated when the message is received by the mailbox. They report they are not getting it until later. Do they mean the message light is delayed? Or do they see the email, and go into MB to find there are no new messages? When was the last system reset? I would leave a test message in a mailbox with the issue, while watching BVM via AvdapMon. That way you can watch it being received, light the light, and being emailed real time.