I would try just using the cleaning cycle with just straight bleach and a lot of it. Pour it straight into the drum.
Is there lots of water sloshing around during the "Cleaning" cycle? If not try adding a few gallons of water to the already filled machine (not too much, just enough to come up to the rubber gasket).
There should be lots of vigorous water movement.
That's my two cents...maybe someone else can add some tips.

The dispensers are removable, I clean these with a bleach solution periodically. Otherwise, I use the cleaning cycle, but I only add bleach up to the fill line in the dispenser = don't add more to the dispenser because it will overflow onto your floor. I've never added it directly to the drum. I keep the door open periodically between loads to air it out.

I wonder if adding too much bleach directly to the drum would have a negative impact on the rubber gasket around the door (long term)? I don't know...I've never tried it, but adding too much bleach sounds risky to me.

Air is your friend and the worlds cheapest cleaner when it comes to odor and mold. Leaving the door open is a must and the best you can do for a front loader. You could put a dehumidifer in your laundry room, run it with the door to your washer open, then run the tub cycle twice with full loads of bleach and see if the smell dissipates. Also check behind the rubber gasket, there could be some debris or mold that could be facilitating the odor.

This happened to me with a Staber washer I have. I tried everything. Everything. I finally took the washer out of service, got me another washer. For this new washer, a Fisher Paykel, we never used anything but powder detergent
and used no softeners, but did use vinegar occasionally.
It never developed the mold problem.

What about the Staber? well, it was stored in a garage for about a year, then brought back into service but got a really good cleaning cycle run through it on its first use.
When stored for the year it was left totally open and airing out. It's never had the mold problem since. I guess the complete drying out did the trick. I only use powder detergents in it now, but still do use some softeners as its in an area with really hard water. It seems to be OK and has been for the last 2 years. NOthing else but the year long drying out seemed to work for me.

Try the cleaning cycle with distilled vinegar

Thanks everyone, it has gotten better. I bought a gallon of vinegar yesterday and going to try tonight.

You might also want to try a dishwasher detergent with lemon.
Run a long, HOT cycle.
Citric acid removes alot of built up gunk and leaves a fresh scent.

My LG washer collects gunk behind the rubber openings. Not in the folds of the rubber, but behind it. I use a towel to remove once a month AND I leave the door open every night. It helps a lot.

Yep, leave the door open till dry. Also HD sells a fantastic washing machine cleaner. This totally eliminated the musty smell in my LG. But it will come right back if you don't leave the door open.