Sometimes male corns can feed erratically during breeding season, but its a little too early for that. If he's an otherwise healthy adult, a few weeks or even a few months won't hurt him. I think its a little too early to start worrying just yet.

Are you feeding him in his cage or outside? If doing one, try the other.

You might try a rat, or a different colored mouse. My adult lavender female used to be a somewhat sporadic feeder on f/t white mice. I ran out of mice and threw in a hooded rat pup, and she went just nuts for him. Got more mice, and she went back to her old ways. So I thought it was the rats, fed her an albino rat, same thing, sporadic feeding. For whatever reason, hooded rats are her favorite. Maybe its something silly like this?

I would give him a couple of weeks off and just leave him be. Then I'd probably try a live mouse and see what happens.