Overheating issue

3weeks ago I built a new pc and it was running perfectly under stress tests,games and every day use but I turned it on today and wile I was messing with the RGB on the case fans the pc shut down due to CPU overheat …temps were hitting over 105degrees instantly.
All fans are working
I tried reseating the aio
My pc spec is this:
I9 12900k
Ryujin 2 360mm aio
32gb ddr5 ram
Rtx 3080
Corsair 1600w psu