find function is not working in mongoose with specified field

So I am making this website where you can see different recipes for food. When browsing for recipes, I want the user to be able to select a category and browse all the dishes that fall under it (i.e dessert, dinner, vegan etc).

I have this function I created in my router file that returns all the dishes that fall under the specified category:

router.get('/showrecipes/:categoryname', (req, res, next) => {

    let nameQuery = {category: req.params.categoryname};

    Recipe.find(nameQuery, (err, recipes) => {
        if (err) throw err;

        res.json(recipes);
    });
});

However, when I try to test it out in Postman, I keep getting Null instead of all the dishes that fall under the category.

All my other functions are correctly working, but this one seems to have issues.

via T-Dot1992