I recenlty connected my dishwasher which had been unused for over a year as I did renovations. I recall it working fine. Yesterday, I ran it and it washed fine but didn't drain.
The drain hose is brand new, there is a high loop, and has no kinks. I checked to make sure the pvc fitting under the sink doesn't have a blockage. When I disconnected the drain hose from the dishwasher, water ran freely into a catch basin. I removed the drain hose connection in the dishwasher and it is clean...I found a little white ball which I assume is the back flow preventer. I was able to visibly inspect the blade and screen and it has some debris but nothing abnormal. I also checked the float assembly and tried a vinegar/baking soda/hot water combo.
The model is msd3205p00ww and serial number is gr600243a. I tried repair clinic but the model number doesn't work.