If the nodes do not have a fully qualified domain name, set the firewall rule for each node to ensure that the firewall port for Windows Remote Management allows you to add inbound traffic on additional nodes. Setting this rule allows Windows Admin Center to reach the nodes and add them to the cluster creation wizard.
Run the following PowerShell command as an administrator on each node:
Set-NetFirewallRule -Name WINRM-HTTP-In-TCP-PUBLIC -RemoteAddress Any
-RemoteAddress
.