There are two main reason why your virtual machine will not be listed:
-
The Host for the VM is not listed because it is not licensed
Navigate to Options > Licensing Settings and select manage hosts check the Host is licensed. If it is not, this will prevent the host from showing and the VM will not be listed.
-
The VM already has a backup job
It is only possible to protect a machine with one backup job. You can however still create a replication job to protect your machine with Hot Standby.