Do you have any guards unassigned? I found that if all of my guards are deployed or assigned to routes than they won't onboard the prisoners.

This just happened to me tonight, cost me a bit of time but lesson learned. I wasn't getting any food delivered. No broken connections, demand was high, but absolutely no supply. I was expanding my prison with a new cell block. For some reason or another my screwy cooks took all of my ingredients to...