Only 1 instances of CPM Enterprise Edition are allowed to perform backup in one account.

Error Message "Only 1 instances of CPM Enterprise Edition are allowed to perform backup in one account." when performing upgrade or installation of CPM server.

Symptom:
When upgrading or installing your CPM server by installing a new instance, you could get the following error:
Only 1 instances of CPM Enterprise Edition are allowed to perform backup in one account. the following instances belong to this edition: {Instance ID Here} (Region: {Region Here}), To use this CPM server for backup, please click on "perform failover" from the main CPM console screen, when no other CPM Server of this edition exist in this AWS account.

Description:
This error is caused by an older CPM instance that is still active with the same AWS account as the new CPM instance. 

Resolution:
In the error description, it should detail the VM instance that is causing the conflict. The VM likely is still in your Instances inventory, and should be terminated. A common mistake is using the "Stop Instance" option, which does not delete the instance, when we should be using "Terminate Instance", which will delete it.

If you need to find more information on which instances are using the CPM product, you can open AWS Marketplace with the same AWS account, and click on your account name on the Top-Right of the window and click "Your Marketplace Software". From here you can find "Cloud Protection Manager" from the list of subscribed software, and click "View Instances" to get a list of all VMs using CPM.