This problem can be caused by a few things..

The drain pump will still try to drain even if there is no water in the dishwasher. Any time you press the cancel drain button it will come on.

First thing to check is to make sure the water is actually still going to the valve.
I have seen some time where the valve either under the sink or downstairs closes, if it's a pin valve the pin can break and plug the hole.

So best to make sure there is water at the dishwasher to start.

Now if there is water at the dishwasher you should then check for the 120 volts at the valve.
The best way to do this is to unplug the wires going to the valve.
Have your meter on 120 AC. And put one pin in to each wire and then start the dishwasher.
If you get 120 volts which should be right away. Then you know the valve is the problem.
You can find the breakdown and part number for the valve here.
Replacement parts for WHIRLPOOL KUDR25SHBL1 | AppliancePartsPros.com

I just noticed this model has a water level switch, which is a pressure switch that gets the pressure from the inside of the dishwasher while it's filling like a regular washer has.

Those have also been giving some problems. If you take it off and take the hose off of it you should be able to blow into the little spout and hear a click. Sometimes just doing that will fix it. But for this problem of no water at all.. I would think you should first check for water at the dishwasher, then check for power at the valve, and if there is water and power. Then blow into the water level control which is found at the bottom of the dishwasher on the right side.

Let us know if you have any questions.