Objects falling through plane

I have a plane that I’m using as my ground and I have a box collider on 2 objects that fall to the ground and a mesh collider on the plane. The objects though don’t stop when they hit the ground they just pass through. None of them are triggers and I can’t figure out why they pass through. Do collisions ignore layers? If so they wouldn’t if they are on the same layer right? Hope some one can help. Thanks!

This could be the so called “bullet through paper” problem. Check this question and see if the case of yours is the same.