Help With RX 570 not loading

[BitcoinBench]

New to the mining world and building computers in general and needing some help here. I built a new 8 GPU rig with rx 570 cards, biostar btc+ mobo, duel power supplies, ethOS. Everything works fine with 1 card plugged in, soon as I plug the second card in the entire rig will not boot. Where do I start trouble shooting this? I'm new to building computers so please be as descriptive as possible.

[xxcsu]

If you want to get some help , please post your full system spec , incl psu rating , how you connecting 2 psu ( what powering what ) what risers are you using , what is your system mem ...

[BitcoinBench]

If you want to get some help , please post your full system spec , incl psu rating , how you connecting 2 psu ( what powering what ) what risers are you using , what is your system mem ...

Right now I'm just using 1 psu, it's corsair hx1200. Risers are Mailiya PCIe Dual Chip PCI-E, GPUs are 8gb, system memory 4gb. Anything else?