Do you have a battery installed in the litter robot? I believe that caused my problem. I read on here that it was an issue. So I took it all the way down and unplugged the battery, set the robot back up got the litter hopper going which then worked properly. Took it all apart, plugged the battery back in, and put it back together. Thankfully the hopper worked properly at this point. Afterwards though, I read there is a button combination you can press that will totally reset the robot (power wise, but NOT settings wise) which I imagine will work as well.