F220 on Miele may indicate a leak; on certain units it may also appear incorrectly. The presence of water and whether the alert repeats determine the next step.
If there is visible water
The manufacturer documentation treats the leak as a fault that requires repair. Turn off the water supply, stop using the appliance, and disconnect it only if the area is dry and it is safe to do so. Do not try another cycle or tilt the appliance to remove water.
If no leak is visible
Miele documents a check after disconnecting and inspecting the outside: if the unit works again without an alert or leak, it may be an incorrect display on affected models. Confirm with support whether this applies to your washer before using that process; if the code appears again, request service.
The manufacturer provides a software update for certain units and specific support when they do not have connectivity. There is no single version or promise of universal compatibility. Check by model whether an applicable update exists and what the procedure is.
To describe visible water, use external leak location. The absence of a puddle by itself does not identify a software fault.
Keep a photo of the first alert and note whether it disappeared after restarting or returned during the wash cycle.