1. Bluetooth is closed.
Reason1: Bluetooth is closed or location permission is denied.2. App cannot connect S9.
Reason:S9 isn't turned on. Reason:S9 is connected by other person. Reason:S9 is in low battery. Reason:S9 hardware error.3. S9 doesn't response.
Reason: S9 hardware error.4. S9 cannot connect WiFi.
Reason: S9 hardware error. Reason:WiFi password is wrong. Reason:WiFi signal is weak. Reason:WiFi Security is unsupported. Reason: WiFi connection exceed limitation. Reason:WiFi is 5G, or wifi is ap disconnector5. S9 cannot connect server.
Reason:S9 hardware error. Reason:Phone doesn't connect WiFi. Reason:Wifi cannot connect server. Reason: Server exception.6. Phone cannot connect Internet.
Reason:Phone doesn't connect WiFi. Reason:Wifi cannot connect Internet. Reason: Server exception.7. Server reject binding S9.
Reason: The number of S9's user exceeds limitation. Reason: User has already bound another balance.