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:

  * Open the charging case and take out the earbuds.

  * Press and hold the touch areas of both earbuds simultaneously for 10 seconds.

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. Use a Q-tip with a bit of rubbing alcohol to gently clean the metal mesh filter under the rubber ear tips.

5. Check whether the soundcore app has turned on the maximum volume limit: Safe Volume--> Limit High Volume.