Problems with connecting the engines with the Micro HKPilot Mega Master Set from Hobbyking. PLeas help

Can someone help me find out Why I can’t get connection between the engines and the flight controller. THe speed controller I am using is the 420 lite DJA. And the engine is the 2312E also from DJI. Pleas come with ideas if you know the reason to the problem. Thanks.

have you pluged them into the pixhawk upside down? it should be black wire top