If you can PING the IP address of the player but SignApps Express does not find it, please try the following:
1. Update to the latest version of SignApps Express.
2. Add SignApps Express to Windows Firewall allow list of programs.
Go to Control Panel > System and Security > Windows Firewall.
Under Windows Firewall, click on "Allow a program through Windows Firewall"
Click on "Allow another program..."
Find SignApps Express on the list and click "Add".
If you do not see SignApps Express, click on "Browse" and located SignApps Express.
Default location is C:\Program Files (x86)\SignApps Express.