PC boots with 1 stick, but not with 2

[CMcC55]

I've recently purchased a dual kit of Corsair Vengeance lpx 2x8GB DDR4 2400mhz ram.

Both sticks individually work fine in slot DDR4_B2. However in the configurations listed inside the motherboard manual for dual channel the computer won't post. Specs are as follows:

CPU: intel core i5 7500 @3.4Ghz
Motherboard: Asrock b250m pro4
GPU: Gtx 1060 3gb
Ram: Corsair Vengeance lpx 16gb 2400mhz DDR4.

All suggestions welcome,
Colm.

 

[skywalkerqq]

the ram should go in the second and fourth slot, have you tried the ram in every slot? this could be a bad motherboard

 

[CMcC55]

the ram should go in the second and fourth slot, have you tried the ram in every slot? this could be a bad motherboard

Yeah i've tried the second and fourth slot, aswell as the 1st and 3rd. could it have to do with changing any frequencys?