1) The vMatrix Server Manager software is not installed on the host or not working properly.
Resolution: Install or re-install vMatrix Server Manager.
2) The host or the zero clients are not connected to the LAN.
Resolution: Connect both the host and the zero clients to the LAN, and make sure the network is fine.
3) There are two or more hosts with the same name. Only one host will show at the client login screen.
Resolution: Change the host names.