If the error message is “The WS-Management service cannot process the request. The class Msvm_RegisteredProfile does not exist in the root/interop namespace” it’s a bug in an HP specific update. Recompiling the .mof should fix it.
run “MOFCOMP %SYSTEMROOT%\System32\WindowsVirtualization.V2.mof”
If receiving “can’t connect” errors for other reasons, it could be because remote management isn’t enabled or alternate creds or an IP is being used to connect to a down-level host.