Please refer to the possible causes:1. Make sure that you've long-pressed the button for 2 seconds and the device has flashed white light 3 times.

2. Make sure your mobile network is functioning properly.

3. Make sure your phone's Bluetooth is turned on and within Bluetooth range.

4. Make sure your device is close to the phone.

5. Close the app and try again.

If you have any other questions, please don't hesitate to contact us for further assistance.