vRanger backup task fails with virtual Machine was not found for group (4039178)

An email is received from vRanger with the following error message:

The job <JOB NAME> was unable to create a task for <VIRTUAL MACHINE>.\r\n\r\nThe inventory item <VIRTUAL MACHINE>(ID:vm-XXX) was not found for group <BACKUP GROUP NAME>. 

This can happen in the following scenarios:

• The VM has been removed from the inventory.
• The VM UUID or VM object ID has changed.
• The VM has been restored from a backup after being deleted.

In order to correct this, go to the vRanger inventory and browse to the Backup Group pane. Expand the backup group specified and remove the VM that has a 'disconnected' tag.