This error code indicates that the water is draining slowly or not draining at all. Most likely, the drain filter is blocked.
To clear the error, check the filter. Unplug the washer, pull it from the wall and remove the rear panel. There will be the drain pump. The filter is located inside the outlet pipe that goes from the pump. Disconnect it and check the filter. Remove debris and/or foreign objects, if any. Reassemble the system and make sure that the end of the drain hose goes at most 6-8 inches down the drain pipe. Put the washer back in its place and launch it. There should be no error on the display screen now.