2 Pack of Universal 3 in 1 Travel Plug Adapter - JACKYLED International Trip Companion Converter for UK,HongKong,CE RoHS Certificated,13A,250V AC Turn on the switch; Unplug all USB cables and plug part of them again. Get help from us. Get help from us. Get help from us. The switch controlling USB Ports is not turned on; The total current of the usb device/devices exceeds the rated current output of the usb ports; The usb ports are dead when using(it is rare to happen). The USB plate of the product is detective from manufacture. Other reasons.