HTTP Delete -Authorization issue

Question

I have an angular application service that calls a web api. The Web API have Get services which they work fine if called from my angular application, however, if HTTP delete is called , i get error (405 (Method Not Allowed). It can't be an issue with CORS since HTTPGET works. Also tested the Delete service via Fiddler , which works fine. the errors occurs when I hit the web api service from my angular application.

here is my service.ts

 constructor(private _http: Http)     
 {
     delusers(id: number) {    
        return this._http.delete(environment.BASE_API_URL + 'Delusers/' + id)
            .map((response: Response) => response.json())
            .do(data => console.log('All' + JSON.stringify(data)))
            .catch(this.handleError);

 }

web api , controller.No issues with Getusers service , only Delusers service cause the issue

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

namespace ERSA.WebAPI.Controllers
{
    [EnableCors(origins: "*", headers: "*", methods: "*")]
    public class ERSAController : ApiController
    {

        ERSAFactory _modelFactory = new ERSAFactory();

        [HttpGet]
        [Route("API/GetUsers/{userID}")]
        public HttpResponseMessage Getuers(string userID)
        {
              ..some code
        }


        [HttpDelete]
        [Route("API/Delusers/{id}")]
        public HttpResponseMessage Delusers(int id)
        {
          ...some code
        }




    }
}

web api config

<system.webServer>
    <handlers>
      <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
      <remove name="OPTIONSVerbHandler" />
      <remove name="TRACEVerbHandler" />
      <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />

    </handlers>

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