1. Check Bluetooth connection
For different Bluetooth devices, the range of connection is different. Try to ensure that the distance between the Bluetooth device and the phone does not exceed the search range of the Bluetooth device. After connecting, try not to have metal or other obstructions between the Bluetooth device and the mobile phone to check whether there are other interference signal，For example: Router, induction cooker, micro-wave oven, etc.
Confirm whether the device is connected to other Bluetooth devices. If the Bluetooth device is a headset, the phone can be connected at the same time, but it can't work at the same time. You can select the headset you want to use on the Bluetooth interface.
2. Reconnect Bluetooth
Un-pair the Bluetooth device, put it back in discovery mode, then pair and connect.
Path: Settings --> Bluetooth --> Click on the right side of the paired device details icon --> click Un-pair --> Re-search again to pair.
3. Check Bluetooth device
Check if your Bluetooth device is turned on and check if the device is fully charged.
Confirm that the Bluetooth device is available on other devices and may be damaged or not compatible with the current device.
4. Restart cellphone
5. If there is still a problem in troubleshooting shown above, please contact after-sales processing.