Sphere falling through floor

Is it always falling through the floor, or only sometimes? Quick things to try: Is it starting out already inside the floor (click on it and look at the green collision capsule. Is it under the floor?) Try raising it a little off the floor so it falls before hitting.

If that doesn't work, then try removing the character controller and replacing it with a rigidbody. Add a sphere collider to it. Now see if that collides with the floor. (Remember to disable your script or you'll get an error about when you try to access the CharacterController). If that still doesn't collide then look at your Time settings. Fixed timestep should be something like 0.02 or 0.01. Last check your Settings->Physics->Layer Collision Matrix. Make sure the two layers of your sphere and ground are enabled to collide

@UnityNoOb18 I solved the issue by making a brand new project that is not based on an existing project, such as Boot Camp Demo

One thing I have discovered is that applying the controls to the ball itself makes the rotation of the object change the direction of the input.

For example: roll onto the left side, and now your left input control is facing down, through the floor. Hitting the ball "left" therefor works to push the ball through the floor plane.