We had exactly this problem. The motor turns but doesn’t turn the brush. Miele we’re not helpful and didn’t reply to the galaxus team. I haven’t had time to return the cleaner and put guarantee may have expired. This isn’t the only problem and we found this item not up to the excellent standard of our other Miele appliances

Hello,
Normally on tiles it should not stop. It happens to me sometimes, but only on carpets.
You can also remove the brush and put it back.