From your limited description: Frosting almost always occurs because there is an air leak in the door, whether top loading or side loading. Warm air is getting in and "dropping out" on the evaporator (cold) coil. Find a way to seal your door better, or, if top loading, place a wet towel over it when it's closed. There's nothing wrong with your unit, it's working just fine, it's the leaks that cause it.