This means that your phone's settings allow fake or mock locations (usually, but not always, through the installation of an app that fakes your location).  GPS Verifier will not work if your phone is set up to allow fake or mock locations.  You must remove the app and disable mock locations on your phone.

To disable mock locations on your Android device:

  1. Go to Settings -> System and select Developer Options.
  2. Click Select mock location app and select Nothing.