Make sure all wires are connected properly specifically the rear cable and the USB cable.
When connecting the cables, make sure they are inserted all the way. If there is a gap (as image below) then it is not completely connected:
It is properly connected when there is no gap between the cables as below image.
Also note that there are arrows on each end of the cables - that is the indicator of which way the cables should go They'll need to be aligned and connected.