Please check if the charging voltage of user device is 5V. If not 5V, please use correct charger. Please check if TOUGH SYSTEM MUSIC can charge other devices, such as iPad, iPhone. Please check if the USB cable inserts entirely, you may need to reconnect the cable. If the problem is still there, you should try to change to another USB cable. If still can’t charge by USB socket, please take (TOUGH SYSTEM MUSIC + CHARGER) to an authorized service agent.