Backup Exec Job Engine is stopping

Hello,

When i start a backup job, the backup exec Job engine is stopping of the backup server after 2 hours.

In task manager i stop de bengine.exe and then i can restart the service for 2 hours.

Why stop the backup exec job engine?

The version is Backup Exec 2012 Version 14 Rev. 1798.1244 (64 bit) installed on a Windows Server 2008 R2

Thanks in advance