After the earphone is charged, the electrical energy is transferred to the battery inside the earphone case through the electronic wire connected to the earphone case for charging. It may be because the battery inside the earcase has been fully charged or there is a problem with the connection between the earcase and the earphone, resulting in the earcase not being charged. It is recommended to check the charging status of the ear housing to confirm whether the connection is normal, or replace the charger and try to recharge.