When Lowe's delivered my washer the delivery guy told me to be sure and leave the washer door opened when not i use. If not all the time then overnight. All the water needs to evaporate from behind the tub and drain. That stops the mold from forming and that is what you are smelling. You can kill the mold with bleach but then harm the seals over time. It's easy and cost nothing to leave the washer door open.