- Check that both the headset and the connected device (i.e., smartphone) are turned on.
- Check that the headset and the transmitting Bluetooth device are connected via Bluetooth A2DP.
- Turn up the volume if it is too low.
- Check that the connected device is playing back.
- If you are connecting a computer to the headset, make sure the audio output setting of the computer is set for a Bluetooth device.
- Pair the headset and the Bluetooth device again.
- Check that the headphone cable is connected firmly.