Are you sure...the temps and humidity were ok?
This seems very strange to me as Corn's are very well known for being a hardy snake. They can adjust to most temp fluctuatons.
How hot was your hot side and what was the humidity?
Also...did you leave a rodent in with hem to eat?
Corns...I should say snakes...don't typically just dry up and die.
I would like to know more about how you were housing them.