On the base plate of the appliance is the anti flood device.
Check the float hasn't stuck and is still activating the anti flood switch.
Check the switch isn't damp or faulty.
Check the wiring to the switch isn't faulty. (You'll need to have, and be able to use, a multimeter to check the wiring between the switch and the main control board in the door).
If all checks out ok, it only leave the main control board in the door as the culprit.
Normally it's the float that is still activating the switch.
Have a look, see what you find.
Hope this helps
Let me know how it goes or if you need more help