VM Backup can be configured to log both success or failure events in the Windows Application event log.
To monitor such events with 3rd party monitoring applications, you will need to define the Event ID details, which you can find below:
All events will come from source "Altaro VM Backup"
Event ID 5000 - Successful Backup event
Event ID 5001 - Warning Backup event
Event ID 5002 - Failed Backup event
Event ID 5003 - Successful Restore or Verification event
Event ID 5004 - Failed Restore or Verification event
Event ID 5005 - Successful Offsite Copy event
Event ID 5007 - Failed Offsite Copy event
A sample Backup event can be seen in the screenshot below: