Check the physical connections — try to reconnect the cards to the risers and the risers to the motherboard. Also find out which card is giving you this code and try to swap the risers to see whether it's the card's or the riser's fault. And if you ask questions and actually want some help, at least spend a few minutes and describe your setup: what motherboard, what card(s), riser(s) and PSU(s), how they're connected etc. Don't make us guess, we've no idea what kind of system you have.