Answered C2 base plate crash

moved to C2 forums section --- this is not an R1 question

 

Other that what you have done? No.
It could be a faulty sensor (make sure you checked the wires back to the main board and none are knocked off)

 

I had the same problem with my C2 printer. The issue is that the aluminum support bracket slopes down toward the front of the printer.
Your options:
1) Contact Robo3D support about the problem. In my case, the sloping was really terrible so I had them send me a new aluminum support bracket and I repaired the printer myself.
2) If the slope is not too bad, you could try shimming the print bed by adding shims to the front two posts and running the Z-Offset wizard. Check the C2 forums for additional information on leveling the print bed and please read all of them before undertaking this task.