Quadcopter did,t fly up when trottle is full

i want to know what are the problem on it. i have a quadcopter with apm 2.8 with flysky i6x transmitter and ia6b receiver. when i have complited setup all motor spin but did,t lift up when i push throttle fullly

You will have to provide more information for any sort of analysis.
A .bin file from the flight controller.
A description of your setup including all the calibrations you have done.
How much of the Wiki have you read?

on a mode 2 configuration i was connect (left up=ch 3 throttle, left down= ch 2 pitch, right up= ch 1 roll, right down=ch 4 yaw) it is correct or not plz check. If not plz share connection