When you set the washer on a spin cycle do you hear the pump running?
And when it comes up E20 is it full of water aswell?
E20 is a draining error code.
If the pump is running fine then it will be a blockage somewere in there.
First thing to check is the drain hose and were it drains to. If it goes under a sink then you need to remove the spigot and make sure this isnt blocked up.
Then remove the filter again and make sure this is all clear.
Then if thats fine you need to lean the washer backwards and look under there and you will see a black hose going from the tub to the pump. Remove this and make sure theres nothing in there aswell.
Once all clear refit the hoses and retry the washer and see how it goes from there.
If still the same then it will be a faulty pump. As the pumps on these can be working ok one minute and then not the next. If left for a bit it can start to work again then. So if this is the case then the pump will need to be replaced.
So check them out and see what you find. But i think this is going to be either a blockage or a faulty pump here.
If you need anymore info just get back to me.