1. Whether the Location Service setting of your mobile phone has been turned on;
2. Whether the network wi-fi signal and mobile phone signal are normal;
3. Generally, when the location service is not opened, Fan Fei app will also suggest you to open it when it is just started;
4. If your Fan Fei application is already open, it will always run in the background when you quit and don't close it. Maybe running again won't tell you the information of locating the opening.
I hope my answer can help you. Please accept it.