I guess some more info might be needed to understand wtf I am not getting right. One physical server runs Server 2019 Datacenter and has only Hyper-V running as Feature. I have installed and updated Windows Admin Center (WAC) on the physical 2019 server on a non default port. (Maybe my first mistake, using a non default port... ) Opened up the firewall, can log in to and browse WAC over TCP HTTP from other clients. All are DHCP, all are on default home Lan (192.168.*). On the 2019 I have 5 virtual machines. A SRV2022, A W11, a couple of W10 and an Azure Stack. I have run the winrm quickconfig on all the machines but still can't register them, could of course be due to non default port. Maybe I should just start over with that. Another thing is that I have not specified a common admin account, for obvious reasons, but I should perhaps also make sure they all have a common admin system account to facilitate the WAC joining.
The non-standard port should not matter. I have WAC onnon-standard oprt because IIS runs on the same server I use port 4443 & neer have a problem. Even though technically you do not have to, I install WAC on EVERY machine I intend to access and it takes care of WinRM The admin account Icreate (Builtin Administrator account gets disabled and renamed) has the same username and password on all machines - otherwise you are in for a world of hurt. Another solution is creating an active directory domain