When the overcurrent protection LED on the UPort 400A is on, it means the downstream device is drawing power over the USB port's limit. Please remove the downstream USB device from the UPort 400A and unplug the upstream USB cable or power source. The UPort 400A should return to normal state. Please check your downstream USB device to make sure it is not malfunctioning and that the design is within USB-IF specification before you replug into the UPort 400A.