**Important:** The custom backend must return the correct HTTP status code to be returned. NGINX does not change the response from the custom default backend.
Using these two headers it's possible to use a custom backend service like [this one](https://github.com/kubernetes/ingress-nginx/tree/master/images/custom-error-pages) that inspects each request and returns a custom error page with the format expected by the client. Please check the example [custom-errors](https://github.com/kubernetes/ingress-nginx/tree/master/docs/examples/customization/custom-errors).