A warning message on the RBS Server: "Cannot resolve public IP address" usually means that the Server does not have Internet access, or that port 3495 is blocked through the firewall, or RBS Support needs to reset your Server Locator record.
The RBS Server attempts to connect to DNS on port 3495 to find its public IP address so it can report that address to its Endpoints.
This message can also mean that the "Locator" registry key has been corrupted somehow, or that it is not the same value that is defined in your license file.
Verify that your Server has an Internet connection and that port 3495 (outbound) is not blocked.
Upgrading the RBS Server (even with the same version number) might also solve this issue. Select the REPAIR option.
If port 3495 is not blocked, file a Support Ticket at http://help.remote-backup.com/