Bad smell in washer

Mix ¼ cup of baking soda with ¼ cup of water and add it to your machine's detergent container. Use four cups of plain white (not apple cider) vinegar to a top-load machine or two cups to a front-load model. Pour the vinegar into the drum. Run a high-temperature cycle.
https://alajavidgentstailor.com/

I had this disgusting problem and learned from a chemist on line:
1) Use HE detergent.
2) Use a TINY amount of detergent.
I use about a tablespoon = 2 short pumps on the Tide dispenser. It is sufficient to totally clean the clothes without feeding the black mold. You will be surprised. The chemist described how a tiny amount does all that is necessary to rearrange the molecules to make dirt magnets. The detergent manufacturers encourage overuse. All the excess detergent just pollutes freshwater after having served no purpose.
3) Leave the door slightly ajar at all times for air circulation. I used the plastic cup lid from the liquid detergent as a prop.
4) I thoroughly cleaned with citric acid (Glisten for dishwasher cleaning) and though it is still somewhat stained, there is no active growth.
5) With the above precautions, I do not have to be constantly cleaning the gasket.

I always leave my door open in between loads because I want the washer to dry out. Top loading washers have less of a seal, but the front loading washer is air tight and dark....perfect for mold.

The front door seal stays moist an will grow mold. The mold smells and must be removed from the seal. To remove the mold you will need to remove by manipulating the seal to get under it. The mold will stink up you towels and other fabrics that have much of a pile to them. I have run my laundry with an oxygen sanitizer that I use to clean beer brewing equipment. This is the only thing that gets the smell out. Sears has a service flash on this but no solution. You might try leaving the door open so the seal can dry.