Thank you guys and sorry, because it was the riser sata power connector that has disconnected.
Now the rig is working great.

Great that one of the best cards in mining like Rx 6800 Xt is not dead as that scared the hell out of me,I also own two of those beasts and I am very happy with their performance so far.I have switched to a riserless motherboard and since then I never regret doing so,I have never seen a more stable motherboard than this one the H510 Pro BTC.
What type of riserless motherboard you own @swogerino? I heard this bad boy are so stable than all those motherboards using risers, I might probably change all my motherboards to riserless motherboards after the bear market does it's worse.
I used to use only Biostar motherboards,with risers and they worked good,served me well from 2016 up until end of 2021.In the 2022 year I decided to buy riserless motherboards,I always buy branded ones because there are a lot of Chinese riserless motherboards which I am not confident to get good service for the long run,so I got with Asrock H510 Pro BTC + and I am extremely happy so far.The only downside if we can call it like that is that it needs a powerful processor to run stable,a minimum of Pentium Gold of Lga 1200 socket,personally I run it with a core i3 to have piece of mind.