Exchange backup license error after 30 days of installation. (4036710)

Exchange backup license error after 30 days of installation.

Customer has one NetVault Server and would like to manage Exchange backups from two sites.
Each site has an Active/Passive cluster setup and the customer wanted to add the cluster Exchange Servers to the NetVault Server via Client Management - Cluster - Create Virtual Client function.
Both virtual Exchange Clients were added successfully and the two Exchange Cluster License Keys where installed on the NetVault Clients with their Machine IDs.
Unfortunately after 30 days the backups failed with a license error.

The Software evaluation period is now 30 days and is a clue to why a backup fails with a license error i.e. the incorrect license key was installed.
Since this is a cluster setup, the Exchange Plugin and license key should not be installed on the Client.
The customer had setup the Exchange virtual Client correctly, but had supplied the Machine ID of the NetVault Exchange Client and therefore installed the license on the Client.
The NetVault Server Machine ID was supplied to the License Department and an Exchange Cluster License Key was generated for two virtual clients i.e. two sites.
This license key has to be installed on the NetVault Server and could now drill down the Exchange Plugin and perform Exchange backups successfully.