Today I have observed the gateways server pointing to the old RMS server which is decommissioned.
Here is the solution:
1. Check the registry key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Operations Manager\3.0\Server Management Groups\<MGName>\Parent Health Services\0
2. Changed the AuthenticationName and NetworkNameto the new RMS Server.
3. Stop the System Management Service
3. Rename the Health Service State folder
4. Start the System Management Service
This solution also useful incase if you are agents pointing to the old RMS server.