E20/E21/C2 on Electrolux, or two beeps or flashes on compatible models, belongs to the family of drain problems. Keep any additional subcode.
Installation, blockage, or suds
The manufacturer documentation also lists E22, E23, and E24. Do not automatically interpret them as different components that need to be replaced. Note whether water remains and whether the appliance tries to pump.
Check for a kinked hose, insertion depth, and height according to the manual. If the hose connects to a siphon, see whether the household drain backs up too. When there is heavy suds, note the dosage and products because they can make draining harder.
Before opening the service access
Confirm that there is a user filter for your PNC. Safely stop and unplug the appliance, let the water cool, and use its gradual draining procedure. Remove the filter only when the controlled drainage is complete; clean it and reinstall it so it seals properly.
See pump filter cleaning to organize the preparation. If there is no authorized access or the drain still fails, ask for assistance. Do not try another wash with water left inside or force the door to get the laundry out.
A pump making noise does not confirm that the path is clear or that the flow rate is sufficient.