Compaq Insight Manager and Backup exec

We have a compaq proliant server running CIM and Backup Exec (plus 4 more the same setup). Every night, around 10 before or after the backup job kicks off this server shows up as “device inaccessible” and then about 20 minutes later it becomes “accessible”. This is the only server out of the 5 that does this. We know it’s related to the backup as we changed the job time and the alarm changed to match the new time.
Any insight?