Get-ServerHealth Status "Unknown"

Hi All,

I've just run a Get-ServerHealth on my EX13 MultiRole Server and its come back with;

[PS] C:\Windows\system32>Get-HealthReport -Identity newreport
WARNING: A server-side Active monitoring operation has failed. Microsoft Exchange Health Manager (MSExchangeHM) service
 may not be running on server newreport. Specific RPC error message: Error 0x6ba (The RPC server is unavailable) from
cli_RpccGenericRequest

Server              State               HealthSet           AlertValue          LastTransitionTime  MonitorCount
------              -----               ---------           ----------          ------------------  ------------
newreport           Unknown             Unknown             Unknown             1/1/0001 1:00:00 AM 1

I've made sure the service is running (of course) I've even gone to the length of restarting the node. 

Has anyone come across this before, or can anyone help?

Thanks,

Ray :)