Asus Rog Crosshair Hero VII Post Code 8

I replaced my psu with a corsair RM750 and I am getting post code 8. I have tried clearing CMOS, re seating my cpu, and got a 8pin+4pin cpu cord. Nothing seems to be working. I can't post at all. Any ideas? This is my setup. Mobo: asus rog crosshair hero vii Cpu: ryzen 7 2700x Gpu: Nvidia geforce 2070 Psu: corsair rm750