I have a front load washer for about a year now & dread doing laundry in.  It has a bad mildewy musty odor and I don't know how to remove it   Someone suggested bleach and someone else suggested vinegar but both weren't sure which.   I have a septic tank and we are on well water.   I never had this problem with a top load washer which I'm seriously thinking of going back to.   I only got the front load because I wanted to conserve water & energy.

Can you advise me?

From what I've read from reviews of front loaders, many recommend
leaving the door open or ajar after each wash.  I think they mentioned
washing down with vinegar good if you haven't been leaving washer
open.     May get better information by searching for your
particular washer and reading reviews.  Good Luck.