Collisions don't work

Unity Engine
1

Every time I press play the objects fall through the ground. The objects doesn’t collide with the other . How can I fix it?[/ATTACH]

6689137--767221--Screenshot (106).png
6689137--767221--Screenshot (106).png1920×1080 359 KB
6689137--767224--Screenshot (104).png
6689137--767224--Screenshot (104).png1920×1080 356 KB

2

I think this is an accidental duplicate of Hi. I have a problem.