Please try this to solve the issue:
You will have to unplug the appliance and remove the bottom front flap.
Then keep some beach towels and shallow container under the filter.
Now, rotate the drain pump filter anti clockwise to open, clean it completely and make sure it is not clogged.
Now, with your fingers check if impellor rotates.
Then you will see a pull tab next to the filter, pull it to open the door.
Now, reconnect everything and plug it back.
Then try an empty wash cycle and if the error returns, I am afraid door lock is faulty and will need replacement.
Please let me know how it goes.