How could I enable it if the Facebook marketplace not working?

You could enable it once you settle down Facebook marketplace not working. And, for it, you must try to visit the marketplace menu, and for its open the Facebook app and next and next. If you are new at Facebook, then you need to look at the top right corner of the screen for the Marketplace icon. https://www.7qasearch.net/blog/facebook-marketplace-not-working/