it’s the Floor (Boden), it has a Frozen Scale of X-2.8 Y-0 Z-2.88 — it’s the Y scale of 0 that’s messing it up. You have to set it to 1 in the Frozen Scale or unfreeze it and do it then, either way works. Everything goes back to normal once the Y Scale is 1 but now the setting for the Gravity is too small at 50 and should be set back to 1000.
The Friction and Bounce settings in the Dynamics tags are wrong try 2-5% for the Bounce (to start) and 50% for the Friction