A friend of mine emailed me last week because he had to do an uninstallation of the management servers, and root management server (RMS) in an environment. He then re-installed the RMS and one of the management servers but the agents would not report to the new management servers. After debugging what he found was that when he re-installed it had kept the same server name for the RMS but he had changed the management group name. As a result the agents would not report correctly.
Summary: If you ever need to uninstall and reinstall your RMS and don’t want to make configuration changes to your agents do not change either the name of the management group or the name of the management server.