X utility will not be able to connect to X Application Server unless certain TCP ports are open in Windows Firewall (or whatever firewall is running on AppServer machine). Before running X, make sure TCP ports 11000 thru 11005 are open for the firewall software / hardware that is protecting the X machine.
Technically, if you are only connecting to AppServer with one client, you only need to open TCP port 11000. The AppServer listens for
connections starting with TCP port 11000 and up. The number of TCP ports that must be open depends on how many clients you are trying to connect to AppServer at the same time. And the total number of client connections allowed depends on the AppServer license issued by X / X.