Cast on Shock missing socketed skill

I have a cast on shock gem level 18 which requires 60 spirit, 178 intelligence.
I am on 179 intelligence and 80 spirit but I am not able to put any skill gem inside cast on shock (I'd like to put Lightning conduit). I've tried all settings regarding gems inside the options but still nothing, if you have any idea how to fix this problem I'd be so thankful