Reason: CORS header ‘Access-Control-Allow-Origin’ does not match ‘(null)’)

I have a simple method accessible by this url:

http://localhost/SeuropWebWebApi/test

If I access it directly throug the browser, I get the response...

The problem comes when I ask the method from my Angular2 application, I try to make a simple request and the response is:

Code: 200 with empty response

If I try to intercept the call using Visual Studio, I notice that the method is not firing...

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://localhost/****/Test. (Reason: CORS header ‘Access-Control-Allow-Origin’ does not match ‘(null)’).

I think that the problem comes from webapi configuration, I tried to enable CORS call using this tag in webconfig:

<httpProtocol>      
      <customHeaders>
        <add name="Access-Control-Allow-Origin" value="*" />        
      </customHeaders>
    </httpProtocol>

and in WebApiConfig Register method:

Dim cors As New System.Web.Http.Cors.EnableCorsAttribute("*", "*", "*")
config.EnableCors()

But nothing works...

Thanks to support