1, if the charging box is used to charge independently, it may be that the charging box has run out of power and can not supply power to the headset;
2. Clean the stains on the metal contacts inside the charging box and the bottom of the headset before trying to charge;
3. Ensure that the lightning to USB cable and power adapter are correctly inserted.
If you cannot charge after the above attempts, the charging box may be damaged, you can contact Apple after-sales service for repair.
Because the AirPods Pro battery is inactive! Solution: Use up the AirPods Pro's power and the charging bay's power, and then plug in the charger to solve the problem.