The REST API request rest/default/V1/guest-carts/:cartId/shipping-information is returning a 404 error with message "Request does not match any route".
REST API 404 error: "Request does not match any route error" at Shipping method selection Magento 2
Just make sure you are making an API request call with POST method.
And it should be:
but how I can update the core API can you please explain more Mar 14, 2019 at 7:49
you can make your own API endpoint instead– fmsthirdMar 14, 2019 at 8:29