I could hear something happening when the flapper was depressed, but no water. It took me a while to diagnose the issue. Service mode indicated the water dispenser was functional. The RO was supplying adequate water pressure. The water valve tested out ok with a volt meter - 880ohms resistance. Pulled the water supply line into the refrigerator to make sure it wasn’t obstructed or frozen. My final diagnosis was either a mechanical failure of the filter bypass (plug in place) or a mechanical failure of the water valve. Replaced both - problem solved!