Remove the TOP COVER of the washer (two screws at the rear of the top cover/slide top cover rearward about an inch & lift off).
Facing the front of the washer---on the top/left of the TUB---there's an accordion- type bellows hose that connects the DETERGENT DISPENSER BOX to the TUB.
Loosen the clamp at the TUB connection & pull off the hose.
Remove the MUSHROOM VALVE (shaped like an umbrella).
Clean off scum/slime accumulation/re-install MUSHROOM VALVE.
Clean the area of the hose that the valve comes in contact with (soap curd/scum).
Re-attach hose and test washer.
Source: LG WM2233HW Leaking soap drawer