B550 PRO4 ram slot proble

Hi

just upgraded my pc,
new
cpu : AMD Ryzen??5 3600 3.6GHz (Turbo 4.2GHz) 6 Core 12 Threads 35MB
mobo : AsRock B550 Pro4 AM4, DDR4, 4733MHz+
ram : Kingston HyperX Fury RGB DDR4 16GB 3200MHz HyperX Fury Ram (HX432C16FB3A/16) (dual rank)

and the problem;
that ram works very fine on slot b1 and b2, pc boots very well (i've been writing now)
but whenever i change slots to a1 or a2, pc doesnt boot at all, i can see rgb lights thats working well
this ram is not on QVL. i tried cmos reset, didnot help


is there any specific info, like "yes single channel kingston only work on b1 or b2"
if no, i will send it back to my retailer, which i do not really want cause i have to dissassembly everything and put somewhere secure till i get mobo back.
please help.