VSS Backups Fail on a Windows Failover Cluster

If you are backing up an application that has been clustered using Windows failover clustering, make sure that the application server value in the volume collection synchronization settings points to a virtual (clustered) IP address. For example, while backing up a clustered SQL server instance, the application server should be set to the SQL server's virtual IP address.

When using an SQL Always-on Availabiity group (AOAG), the application server of the volume collection should be set to the SQL server's physical IP address.