DIAGNOSIS Mold and mildew are growing in the damp folds of the door gasket and in the detergent dispenser. Clean cycles with hot water help, but they miss the nooks where gunk hides.
FIX 1) Wipe down the entire rubber door gasket. Pull back every fold and clean with a 50/50 mix of white vinegar and water. 2) Pull out the detergent dispenser drawer and soak it in hot, soapy water. Scrub the cavity it slides into. 3) Run a Tub Clean cycle with a washing machine cleaner (not just bleach). Leave the door and detergent drawer OPEN after every wash to let it dry out completely.
IF THAT DIDN'T WORK Check the drain pump filter and the small hose that runs from the detergent drawer to the tub. They can get clogged with stagnant, smelly residue.
HEADS UP Using too much detergent or fabric softener is a major cause. These products build up in the machine. Stick to 1-2 tablespoons of HE detergent max, and consider skipping softener altogether.