It is best to feed them in their home.
Also try leaving everything in its cage when you are feeding it such as water bowl, hide boxes, decor, etc.
Like what kaorte said, they only eat when they feel secure.
Quick Tip:

If you want to feed your snake but it is still in its hide box, try leaving the ESCAPE PROOF tub that the rat/mouse is in next to the snakes cage with its screen OPEN thus letting my odor into his cage thus alerting him food his coming. Since the snakes and rodents cages are open, be in the room supervising. About 15-30 minutes will yield to roaming and rapid tongue flicking of your snake.