The Windows client seems to make a connection with the Backup Exec server
( the icon becomes green) , but there is also a error:

Client has not logged in
This error code does not have a specific cours of action defined for a
resolution. Please consult your manual for additional information.

I cannot view the job-logs or other issues.

Pinging with the host/dns name is ok. I also be able to make contact (the
same client) with ANOTHER backup exec server.

Please help