The error message "Proxy Agent Signature Verification Failed" is encountered, typically when the target machine has a BDRSuite Integration Service (BIS) agent installed, which has been pushed by a different backup server or BDRSuite Client. This error arises due to a mismatch in the Unique Identification Number (UUID) used for communication between the BDRSuite Backup Server or BDRSuite Client and the BIS agent on the target host. Each BIS agent possesses a unique UUID, and when there is a UUID mismatch, subsequent backups fail with the "Proxy Agent Signature Verification Failed" error.

Before proceeding with the solutions, ensure the following:

1. The target host is not added to another BDRSuite server or BDRSuite client.

2. The VIS agent is not being used by another BDRSuite server or BDRSuite client.

If the target host is already added to another BDRSuite server or BDRSuite client, you have two options:

Option 1: Continue using the existing BDRSuite server or BDRSuite client:

a) Remove the host entry from the BDRSuite server or BDRSuite client user interface.

b) Uninstall the VIS agent from the target host using these steps:

1. Go to the Control Panel.
2. Select "Programs and Features" and click "Programs."
3. Locate "BDRSuiteIntegrationService" and click "Uninstall."
   

Option 2: If you still want to configure backups from the current BDR server or BDRSuite client:

a) Remove the host entry from the BDR server or BDRSuite client user interface.

b) Uninstall the VIS agent from the target host using the steps mentioned above.

c) Once these steps are completed, re-add the target host to the backup server or BDRSuite client and configure the backups.