If you want to deploy Feature Update on Windows Server, you need to meet the pre-requisites, get your Active Directory ready, and then perform the upgrade.

If you want to configure Host Guardian Service on Windows Server, install the Server role and configure it, check out this tutorial.

Both domain controllers are on the same ESXI server so now thinking that may be the issue??? Also ensured windows firewall is off on all servers and clients. Any help would be greatly appreciated.