Why does updating cart item quantity return a 404 error?

[styleshop27]

I am using a checkbox to add an item to a cart, and when it is unchecked, remove the item from the cart. Below is the error I am getting when trying to update the quantity of the item in the cart (removing it). 

POST https://mywebsite.com/cart/update 404 (Not Found)

I tried replacing "routes.cart_update_url" with "routes.cart_add_url" and the error changes from (Not Found) to (Bad Request) meaning the request is actually made with the add url, just the body is invalid as it is not the proper format. I can't figure out why the "routes.cart_update_url" is causing a (Not Found). 

Below is my JavaScript Code (protector is just a variable that holds the variant ID):

let updates = {
   protector: 0
};
fetch(`${routes.cart_update_url}`, {
   method: 'POST',
   headers: {
      'Content-Type': 'application/json'
   },
   body: JSON.stringify({ updates })
})
.then(response => response.json())
.then((response) => {
   this.window.SLIDECART_UPDATE(response);
})
.catch((error) => {
   console.error('Error:', error);
});

[PaulNewton]

https://community.shopify.com/c/hydrogen-headless-and-storefront/read-before-posting-custom-storefro... 

This is the hydrogen subforum for headless storefront architectures

Not for the online-sales channel themes.

Unless your doing something hinky with hydrogen you can report your own content to have it moved to the proper forum in the the three dot kebab menu on your post.

Either design or techQ&A.

 https://shopify.dev/docs/custom-storefronts/hydrogen/getting-started