If you smell a musky smell around your washing machine, its very likely that your washing machine has a mold issue. This would happen, especially, if you washing machine is not left to dry sufficiently and in the humid environment and the "dirty" remnants from the laundry, mold will grow in the washing machine itself. Behind the drum, in areas not visible to the eye.
It is advisable to get professional cleaners to help dismantle the washing machine 2 - 3 times a year to do a thorough cleaning. These professionals help to dismantle the washing machine and take out the drum and all the pipes to clean. They typically use chemical cleaners, but you can request for them to use your own set of natural cleaning products.
For us, we got them to use Soapnut Republic Multi-purpose cleaner, which is very effective in cleaning mold.
See the difference?