Musky smell and or marks on clothes
Inspect the door seal for any signs of gunge, slime .
Get your fingers into the seal.
You can even remove the lifters to inspect the drum.Here is how to remove lifters! ( will open new tab )
Here are a few pictures of what your machine could look like
If you overdose on liquid you get stale smells on clothes , small black marks that wash off ( if the marks don`t wash off it might be oil probably bearings failed ).
There is only one solution DON`T overdose and use Biological powder as this keeps your machine clean aswell.If for any reason you can`t use biological powder then use it for what you can eg curtains , dogs towels etc