First thing I’d try to do is to guess how the door and it’s lock operates. Some cheapest options I encountered (not in washing machines, but safety screens on factory equipment) were either bare pins meeting each other or a reed switch reacting to a magnet in the door or the locking mechanism - thus closing the circuit. You seem to have an indicator to directly tell you if the door is closed\locked?, so you can try to look into this right after reseting it anew. I’m not sure if it’d lead anywhere, but it may be simplier to cross out from the list than other issues.