I would like to share how I solved an issue.
Situation: Master server (10.3.0) is running on Windows server. Disk C:\ became full. After freeing the disk space and restarting the server it was impossible to connect. Java GUI returned this message:
Unable to login, status: 537. Connection to the NetBackup database was not successful. Ensure that the database service is running.
In Windows Event log there are hundreds of events:
NBDB/(nouser)@[::1]:54816 pooler error: server login has been failing, try again later (server_login_retry)
This issue has been resolved by repairing the installation (installation media -> Install -> Repair).
