After water turns on, nothing else happens

We have a freestanding Kenmore Dishwasher model 17425790 push button and a rotary nob for the cycles. When I first plugged it in and turned on the water ( which hooks onto the sink faucet ) the water turned on and everything seemed fine. But roughly 20 seconds later the water stopped in the machine and then just a soft humming started. The cycles seem to still be in motion because the nob is slowly turning and it is hot inside the dishwasher but that's it. I have turned it on and off. I have tried turning the water off and running the cycle. I have made triple sure the door is closed. I have attempted to restart the cycle.The water level *seems* fine. What do I do ? Please help!