Hi everybody !
I have some issues in my scene. First i saw the backgound is like non existent, balls are simply going through 
I have applied transforms to it, i added a solidify modifier for a thickness of 10cm and applied it. Here are the physics settings:
I also tested with different origins (mass surface/mass volume), same issue. I really can’t figure it out
Then, there is a second issue. This time with the box storing balls. One green ball seems not working while touching the bottom of the box (the good bouncing well, the wrong is going through):
Here the video:
Here the blend file:
rigid_body_billes.blend (5.6 MB)