M.N.
I can't see the other answers here, but I have had the same problem repeatedly. There are some products you can buy to take care of it. There is a tub wash cycle that I can choose on my maching. I don't know if that is standard. Afresh makes little tablets that you put into the tub (not the detergent area) that work. Also, Clorox makes a tub cleaner product that seemed to work really well. You are supposed to keep the door open all the time, which I find completely obnoxious. The Afresh says to use it monthly. The first time I used it, the smell was so bad I think I ran it three times and it went away. I know it is an incredibly common problem with the front loaders.