Check the water mains pressure is enough, at least 1 bar is needed to open inlet valve
If valve opens the tray will fill, if the tray does not fill and water pressure is ok, check the valve.
If tray fills the pump must start running after 1 min, if the pump fails to run check power to pump
No power at pump its board or electrical, check further to find fault
If the pump gets warm and or runs and does not push the water up then remove and check the pump