My Diplomat ADP 8242 won't restart?

My Diplomat ADP 8242 finishes it's cycle and the indicator light stays flashing. If I turn it off and on again the light stays flashing and I hear 2 beeps. Pressing the black button makes no difference. In the past when this has happened I have fiddled with the mains supply and then the dishwasher sorted itself out. This time it is completely ignoring me!