I’ve created 2 objects: ground and a person, then I added to each of them boxcoliders, and a rigidBody to person. So when I start my game, the person don’t fall on the ground untill the end(don’t connet with the ground). Why? Plese help 
Is it a 2D game or a 3D one?
In any way, you could try setting the RigidBody’s collisions detection to “continuous”, that might fix your problem