Example: If your Server ID (SID) is '1000', and your 'Server' field shows sNNNN.pbxtra.fonality.com then you should change the 'Server' field to sNNNNx.pbxtra.fonality.com
NOTE: You must have TCP port 6600 open on your router/firewall and forwarding to your PBXtra in order to allow remote HUD clients to connect to your PBXtra . Please see How do I verify ports for remote operations?