Try this solution
1. Make sure that the earbuds are making contact with the pins in the charging case
You should hear a small 'click' sound when the earbuds are sat in the case correctly and the pins have made contact with the charging points on the earbuds.
Please ensure that if you are using the largest size of ear tips or ear fins then they are not preventing the earbuds from sitting correctly in their cradle in the charging case and making contact with the pins.
2. Clean your charging case with a suitable cloth or an alcohol cleaning pad
There should be no obstruction in the charging case stopping the earbud from being properly seated. Be sure to remove any obstruction or debris from the charging case, as well as on and around the charging contacts. If there is sweat, liquid or obstruction on the charging contacts within the case, corrosion may occur. In this situation, please clean the charging terminal or earphones with a suitable cloth or alcohol cleaning pad before charging. Cotton buds can also be used to get into the charging case to gently clean around the charging pins and remove any obstructions.
3. Clean your earbuds and eartips
Please note: Take caution not to allow any moisture to enter the earphones through the ports. In addition, do not force any dirt or debris into the ports and do not blow air into or vacuum the earphones as this could risk damaging them.
1
Remove the ear tips and gently wipe them with a clean, damp cloth - using water or an alcohol-based solution.
Let the tips dry completely before you put them back on to the earbuds.
2
Start cleaning the earbuds using a dry soft brush to gently clear any debris out of the earbud driver grilles. Do not use brushes with any kind of metallic bristles.
3
Hold the earbuds with the grille facing down so that any debris can fall out of the earbud during the cleaning process. Do this gently to ensure that debris is not pushed further into the earbud.
4
If, after dry brushing, any wax remains, dip a cotton bud in surgical spirit, tap off excess fluid and then wipe the bud to remove the wax. The spirit will dry quickly and will not damage your earbuds.
5
Finally, take an alcohol wipe and wipe it all over the earbuds. This will clean any remaining dirt/debris and disinfect the earbuds.
6
Once the ear tips have dried completely, reattach them to your earbuds.
4. Perform a factory reset of your earbuds
1
Place both earphones in the case.
2
Press and hold down on both earphones for 10 seconds until the earbud status lights briefly turn blue.
3
At this point, you can release the surface of the earphones.
4
The earphones should start to flash rapidly, which means it is in the process of factory resetting.
5
Once the earphones have stopped flashing, the reset procedure is complete and the earbuds will no longer remember any of the devices that have previously paired with them.
6
Remove the earbuds from your device's Bluetooth settings
7
Perform the initial setup procedure from the beginning. If you don't remember how you can find the instructions below
5. Drain the battery completely
Please leave the unresponsive earbud outside the charging case overnight to completely drain it out of its remaining battery. After that, please put it back in the charging case and see if it is working and LED is flashing as it should.