To fix this issue, please try the steps below:

1. Turn on "Absolute Volume" in the developer options or select "the Bluetooth device volume to sync with the phone" in the Bluetooth settings.

2. Make sure the charging case has enough power and reset the earbuds by following the steps below:

  - Put the earbuds into the charging case and then take them out. Make sure that the earbuds are connected to the charging case. If you place the left and right earbuds in the charging case and the LED indicators on the charging case light up for 4 seconds and then go off, it means they are connected properly.

   - Within one minute of the earbuds powering on, tap and hold the touch area--top of the earbud stem on both earbuds for 10 seconds until you hear a notification sound.

3. Clear all the pairing records on your phone and re-pair your earbuds. Turn the volume down one notch on your phone. Then turn up the volume of both your phone and earbuds with the music/video to the maximum. 

4. Gently clean the mesh filter with a hard-bristled brush lightly moistened with alcohol.

If you have any more issues or your issue has not been resolved, please contact us for further assistance.