Bdtjtk

Configuration: Angular 6 sends an http request; it is localhost:4200. The request is to Entity Framework (standard .net) hosted on IIS at port 4000.
It sends a POST to /api/Registration/CreateNew passing the data object in the body.
The controller get functions were tested as non-CORS requests using the browser sending directly to localhost:4000 and they work properly.

The error: "Access to XMLHttpRequest at 'http://localhost:4000/api/Registration/CreateNew' from origin 'http://localhost:4200' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: registration:1 It does not have HTTP ok status."

The following is a fiddler snapshot of the headers Request from 4200 (Angular) and the response.

IIS Entity Framework WebConfig:

  <appSettings>

<add key="webpages:Version" value="3.0.0.0" />

<add key="webpages:Enabled" value="false" />

<add key="ClientValidationEnabled" value="true" />

<add key="UnobtrusiveJavaScriptEnabled" value="true" />



<add key="allowedCorsOrigins" value="http://localhost:4200" />

<add key="allowedCorsMethods" value="get, post, put, delete, options, batch" />

<add key="allowedCorsHeaders" value="*" />

  </appSettings>

App_Start/WebApiConfig.cs

        public static void Register(HttpConfiguration config)

    {

        config.EnableCors();



        // Web API configuration and services

        // Web API routes

        config.MapHttpAttributeRoutes();

        config.Routes.MapHttpRoute(

            name: "DefaultApi",

            routeTemplate: "api/{controller}/{id}",

            defaults: new { id = RouteParameter.Optional }

        );

    }

Also added the class attribute to the Controller Class:

    [RoutePrefix("api/Registration")]

[EnableCors(origins: "http://localhost:4200", headers: "*", methods: "*")]

public class RegistrationController : ApiController

{

According to the Fiddler Headers shown above, it would appear that CORS requests should be happening. I have breakpoints on the IIS Controller lines and they never get hit so it would appear this (if I understand it correctly) "pre-flight" request is failing to allow the CORS request.

Unfortunately, this is a sizable chunk of code and hard to put up on the web.

According to your response error message, it return 404 error, not 401 error.
404 error means he couldn't find the page.

As far as I know, the CORS related error is 401 as like below:

I suggest you could check your application to make sure you have used to the right url to access web api.