First of all, it may be caused by the earphone power out, it is recommended that the user check whether the earphone has power, if the earphone is out of power, you can put the earphone back to the charging box and charge it again, if the earphone box is also out of power, the earphone box is connected to the charger to charge it together.
If you are sure that the earphones have electricity, you can put both earphones back into the charging box and then take them out to try. If there is still only one sound and one has no sound, it may also be the audio problem, it is recommended that the user change an audio to try.
After eliminating the audio problem, it is recommended that the user shut down the phone and restart it, and then try to reconnect the Bluetooth headset, or you can directly open the phone to cancel the Bluetooth headset pairing, reset the headset, and then re-pair it.