Mold can easily grow on clothes and towels if they have too much moisture. It's a good thing there are quite a few solutions you can do at home to get rid of that mold smell.
Some good ones include the use of basic household ingredients, which are easy to use and inexpensive. Learn more here.
https://kellysdrycleaners.com/blog/6-ways-to-get-mold-smell-out-of-clothes-and-towels/