If you feed P/K or F/T, try leaving the prey in overnight. It's something I have to do with some of my snakes, and not just my BP's. They simply won't eat if there is light. You can attempt to black out the cage by covering it with a black sheet during the day time, but for me, leaving prey in overnight is a bit easier.

But like everyone else has said, sometimes they just go off feed for awhile. They're quirky snakes! Good luck!