Try the following:
- Bring the headset's left (L) and right (R) units within about 25 cm of each other.
- Set the headset's left (L) and right (R) units in the charging case, and then take them out again.
- Charge the headset's left (L) and right (R) units.
- Turn up the volume on the headset.
If you are using the headset via a Bluetooth connection, turn up the volume on your smartphone.
- Check whether the sound is playing back correctly on your smartphone.
- Bring the headset's left and right units closer together.
If the headset's left and right units are separated, sound may only come from the left (L) unit.
- Use a pen, paperclip, or similar object to press the RESTART button on the charging case.
- Hold down buttons (1) and (2) for about 30 seconds until the green indicators flash 2 times (Restarting).
- After deleting the device information for the headset from your smartphone, pair them once again.