title: Post failing in React app
body: <p>This is the function I'm using to POST data,</p>
  
  <pre><code>export function postData(url, senderId, receiverId, mediaId){
    return fetch(url, { headers: { 'Content-type': 'application/json' },
                        credentials: 'include',
                        mode: 'no-cors',
                        method: 'POST',
                        body: JSON.stringify({"senderId": senderId, "receiverId": receiverId, "mediaId": mediaId})
    })
      .then((response) =&gt; { console.log('Status: ', response.status);})
      .catch((error) =&gt;{ console.log("Request failed: ", error) ;
  
      });
  
  }
  </code></pre>
  
  <p>This is the component that makes the POST</p>
  
  <pre><code>class HomePage extends React.Component{
  ......
   handleSubmit(data){
     ......
      postData(post_url, this.state.user.yguid, this.state.receiverId, this.state.mediaId);
  
    }
  
  render(){
      return(
          &lt;div className="col-md-2 left-pane"&gt;
            &lt;Sidebar handleSubmit= {this.handleSubmit}/&gt;
          &lt;/div&gt;
  
      );
    }
  
  }
  </code></pre>
  
  <p>This is the Server endpoint handling the POST</p>
  
  <pre><code> @RequestMapping(value = "/send/",
                      method = RequestMethod.POST)
      @ResponseBody
      public ResponseEntity&lt;Void&gt; send(@RequestBody Message message) {
  
          try {
              controller.send(message);
          } catch (Exception e) {
  
          }
  
          return new ResponseEntity(HttpStatus.OK);
      }
  </code></pre>
  
  <p>I continue to get the following error message,</p>
  
  <pre><code>POST http://localhost:9000/myserver/send/ 415 ()
  </code></pre>
  
  <p>What am I doing wrong?</p>