title: Http request fail on NativeScript Angular
body: <p>I have the Groceries tutorial, working. Then I go to the user service and change the URL of the login: </p>
  
  <pre><code>login(user: User) {
  let headers = new Headers();
  headers.append("Content-Type", "application/json");
  
  return this.http.post(
    "http://ws.u-vox.com/api/noauth/loginvenue",
    JSON.stringify({
      username: user.email,
      password: user.password,
    }),
    { headers: headers }
  )
  .map(response =&gt; response.json())
  .do(data =&gt; {
    Config.token = data.Result.access_token;
  })
  .catch(this.handleErrors);
  }
  
  handleErrors(error: Response) {
  console.log(JSON.stringify(error.json()));
  return Observable.throw(error);
  }
  </code></pre>
  
  <p>When I press sign in I would expect a http message and a JSON on the terminal. 
  But instead I'm getting this mess, and I don't know what is happening.</p>
  
  <pre><code>CONSOLE LOG file:///app/shared/user/user.service.js:38:20: {"line":993,"column":38,"sourceURL":"file:///app/tns_modules/nativescript-angular/zone-js/dist/zone-nativescript.js","originalStack":"ZoneAwareError@file:///app/tns_modules/nativescript-angular/zone-js/dist/zone-nativescript.js:993:38\nfile:///app/tns_modules/tns-core-modules/http/http-request/http-request.js:86:37\nUIApplicationMain@[native code]\nstart@file:///app/tns_modules/tns-core-modules/application/application.js:211:26\nbootstrapApp@file:///app/tns_modules/nativescript-angular/platform-common.js:72:28\nbootstrapModule@file:///app/tns_modules/nativescript-angular/platform-common.js:60:26\nanonymous@file:///app/main.js:7:57\nevaluate@[native code]\nmoduleEvaluation@[native code]\n[native code]\npromiseReactionJob@[native code]","zoneAwareStack":"file:///app/tns_modules/tns-core-modules/http/http-request/http-request.js:86:37 [&lt;root&gt;]\nUIApplicationMain@[native code] [&lt;root&gt;]\nstart@file:///app/tns_modules/tns-core-modules/application/applicati
  CONSOLE ERROR file:///app/tns_modules/nativescript-angular/zone-js/dist/zone-nativescript.js:569:26: Unhandled Promise rejection: Animation cancelled. ; Zone: &lt;root&gt; ; Task: null ; Value: Error: Animation cancelled. _rejectAnimationFinishedPromise@file:///app/tns_modules/tns-core-modules/ui/animation/animation-common.js:98:31 [&lt;root&gt;]
  </code></pre>
  
  <p>My endpoint works outside NativeScript app:</p>
  
  <pre><code>HTTP/1.1 200 OK
  Server: nginx/1.10.3 (Ubuntu)
  Content-Type: application/json
  Transfer-Encoding: chunked
  Connection: close
  Cache-Control: no-cache, private
  Date: Thu, 28 Dec 2017 15:00:39 GMT
  Allow: POST
  
  {"username ... }
  </code></pre>