If you hear a "bong" sound, it means GSX is working perfectly, and it's just trying to tell you something about *why* you cannot use GSX there. But, it's possible you might have turned off all notifications, so you don't know what GSX is trying to tell you.
- Check you have the Verbosity slider in GSX Settings to the maximum setting
- Check you don't have inadvertently disabled the Simconnect text messages, under Options->General->Information->Message Text.