Water has leaked in to the base tray & operated the flood switch. Best thing to do is pull it forward from under the bench. Put a towel on floor around the rear of base to catch the water and then tip it backward as far as you can until all the water is out of base tray. Dishwasher will then go back to normal running. If the E4 returns after one or two washes then there may be a leak and further investigation will be necessary to fix the leak.
Lincoln Appliance NZ