E20 code on my ZWD1272 ?

I have a ZWD1272 which is stopping and flashing the E20 code. It seems to happen in the last 6min of a wash on what I would guest to be the draining. I have drained using the tube by the pump and then rotated the pump to clean any debris. I have also unhooked the wash pipe and poured water through that as well to clear it. It is still not draining and I have not emptied warder from the waste pump and tube beside the pump.