System State Backup fails, BE 2014

I backup System State on my servers once a week, and about half of them fail every time.  The error message is either:

Final error: 0xe000ff15 - A communications failure has occurred with a System State resource.
Final error category: Resource Errors.

or

Final error: 0xe00084f8 - The network connection to the Backup Exec Remote Agent has been lost. Check for network errors.
Final error category: Resource Errors.

Symantec's solution is to open more ports or make registery changes.  The more ports didn't help, and I'm not eager to make changes in the registery.  I have another backup server on a different domain, and the system state backups never fail on that one, and it is configured exactly the same.

Thanks,

Rivdog