I recently had a problem adding a host to a VMM server – all the obvious things had been checked. WinRM was enabled, firewall rules were in place. Service account had admin rights and DNS was correct.
Still, every time I attempted to add the host an error occurred:
“Error (20408) VMM could not get the specified instance Microsoft:{668f165d-4dae-bcb6-5007ff1fc2e8} of class http://schemas.microsoft.com/wbem/wsman/1/wmi/root/standardcimv2/MSFT_NetAdapterRssSettingData on the server server.fqdn. The operation failed with error NO_PARAM”
In this instance, the server was a 2016 one which has been upgraded from 2012 R2. The fix was bizarre. Save all VMs and remove the vswitches so that only normal physical adapters remain and then recreate the vswitches. The config was identical but clearly, something behind the scenes was wrong and recreating the vswitches worked. Retrying the same job on VMM resulted in success and the host was added to VMM.