first of all remove dishwasher drain hose from under sink counter. push screw driver into drain nipple to unblock , look into hose end to see if its clear .put hose back on +try cancel drain again +see what happens. if it does not drain remove kick plate , remove hose from drain check valve attached to motor on right side .un thread drain check valve .+remove check for crap inside ,reinstall valve tighten snuggly .do not over tighten,replace hose ,try again