If you have a Perpetual per-socket license installed on the backup server, and you want to add a backup appliance to the backup infrastructure, you must install an additional Perpetual per-instance license or a subscription license. When you install an additional license, the new license is automatically merged with the existing Perpetual per-socket license. For details on the merging process, see the Veeam Backup & Replication User Guide, section Merging Licenses.
If you do not install an additional Perpetual per-instance license or a subscription license, you will be able to use one free license instance per each socket (maximum 6 free instances per license). After you exceed the limit of free instances, Veeam Backup for Google Cloud backup policies protecting resources that are not covered by the license will fail.
To obtain an additional license, contact a Veeam sales representative at Sales Inquiry.