c# - 405 (Method Not Allowed) when POST from Angular 2 app

I'm a bit desperate with this issue. I'm new on angular 2 and .net and I trying to build a simple application. I programmed an api rest in c#. When i call a GET method from angular it works fine, but not POSTmethod. I receive 405 (Method not allowed) all the time, but if i call the post with postman all works. I see lots of issues with the same problem, but they doesn't work for me. I have CORS enabled. Here's my code:

Angular

    sendPtipo(delegacion,municipio,ejercicio,recinto,tipo){
    let headers = new Headers({ 'Content-Type': 'application/x-www-form-urlencoded' });
    let options = new RequestOptions({ headers: headers });
    let urlPtipo ='http://localhost:50790/ApiProductoTipo/CalculaPTRecinto';
    let body ='delegacion='+delegacion+'&municipio='+municipio+'&recinto='+recinto+'&ejercicio='+ejercicio+'&tipo'+tipo;

return this._http.post(urlPtipo , body , options)
               .map(data => {alert('ok');})
               .catch(this.handleError);
}

private extractData(res: Response) {
    let body = res.json();
    return body.data || {};
}

private handleError(error: Response) {
    console.error(error);
    return Observable.throw(error.json().error || 'Server error');
}}

Api rest in C#

using System.Collections.Generic;
using System.Web.Http;
using AppName.Models;
using AppName.Service;
using System.Linq;
using AppName.ViewModels;
using System.Net.Http;
using System.Net;
using System.Web.Http.Cors;

namespace Api.Services
{
    // Allow CORS for all origins. (Caution!)
   //[EnableCors(origins: "*", headers: "*", methods: "*")]
    public class ApiProductoTipoController : ApiController
    {
        private readonly IProductoTipoService productoTipoService;

        public HttpResponseMessage Options()
        {
            return new HttpResponseMessage { StatusCode = HttpStatusCode.OK };
        }

        public ApiProductoTipoController(IProductoTipoService productoTipoService)
        {
            this.productoTipoService = productoTipoService;
        }

        [HttpPost]
        [Route("~/ApiProductoTipo/CalculaPTRecinto")]
        public HttpResponseMessage CalculaPTRecinto([FromBody]int delegacion, int municipio, int ninterno, int ejercicio, string tipo)
        {        
            if (this.productoTipoService.CalculaPTRecinto(delegacion, municipio, ninterno, ejercicio, tipo) != 0)
            {
                return Request.CreateResponse(HttpStatusCode.OK);
            }
            else
            {
                return Request.CreateResponse(HttpStatusCode.BadRequest);
            }
        }
    }}

webapiconfig.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web.Http;
using System.Web.Http.Cors;

namespace Web
{
    public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
            //Enable cors
            var cors = new EnableCorsAttribute("*", "accept,accesstoken,authorization,cache-control,pragma,content-type,origin", "GET,PUT,POST,DELETE,TRACE,HEAD,OPTIONS");

            //var cors = new EnableCorsAttribute("*", "*", "*");

            config.EnableCors(cors);

            //Configuramos el MapRoute
            config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "{controller}/{id}",
                defaults: new { id = RouteParameter.Optional }
            );

            config.Routes.MapHttpRoute(
                name: "ApiWithAction",
                routeTemplate: "{controller}/{action}/{id}",
                defaults: new { action = RouteParameter.Optional, id = RouteParameter.Optional }
            );
        }


    }
}

Log

headers:Headers
ok:false
status:405
statusText:"Method Not Allowed"
type:2
url:"http://localhost:50790/ApiProductoTipo/CalculaPTRecinto"
_body:"{"Message":"The requested resource does not support http method 'POST'."}"

Any idea? Thank you for reading!

Edit: this was the response of Postman 200 OK

Cache-Control →no-cache
Content-Length →0
Date →Fri, 26 May 2017 09:48:05 GMT
Expires →-1
Pragma →no-cache
Server →Microsoft-IIS/10.0
X-AspNet-Version →4.0.30319
X-Powered-By →ASP.NET
X-SourceFiles →=?UTF-8?B?QzpcVXNlcnNcNzAyNTU3MjFKXERlc2t0b3BcQXBpUHJvZHVjdG9UaXBvXFdlYlxBcGlQcm9kdWN0b1RpcG9cQ2FsY3VsYVBUUmVjaW50bw==?=