First off, the fact that the dispenser is leaking at all is usually a...

...strong indicator that too much detergent is being used.

Use:

HE: (2) Tablespoons Per Wash load

HE 2X: (1) Tablespoon

HE 3X: (1) Teaspoon

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