title: Android Volley error.getMessage() is blank
body: <p>So I am making a POST JSonObjectRequest to my server and when it is successful everything works and the info is posted, but if there is an error and I try to display it in a toast, it shows up as blank. Here is my request: </p>
  
  <pre><code>private void logUserIn() {
      final String URL = Globals.BASE_URL +"/auth/login/";
      // Post params to be sent to the server
      HashMap&lt;String, String&gt; params = new HashMap&lt;String, String&gt;();
      params.put("username", username.getText().toString());
      params.put("password", password.getText().toString());
  
      JsonObjectRequest req = new JsonObjectRequest(URL, new JSONObject(params),
              new Response.Listener&lt;JSONObject&gt;() {
                  @Override
                  public void onResponse(JSONObject response) {
                      try {
                          Log.d("Log In User", response.toString());
  
                          //logged in db, changes screens
                          Intent nextScreen = new Intent(getApplicationContext(), MyProfile.class);
                          startActivity(nextScreen);
                      } catch (JSONException e) {
                          e.printStackTrace();
                      }
                  }
              }, new Response.ErrorListener() {
          @Override
          public void onErrorResponse(VolleyError error) {
              Toast.makeText(getApplicationContext(), error.getMessage(), Toast.LENGTH_SHORT).show();
              VolleyLog.e("Error: ", error.getMessage());
          }
      });
  
      // add the request object to the queue to be executed
      Globals.mRequestQueue.add(req);
  }
  </code></pre>
  
  <p>error.getMessage() is always blank. Here is my response (tested using CURL) when the server returns an error:</p>
  
  <p>{
      "non_field_errors": [
          "Unable to login with provided credentials."
      ]
  }</p>
  
  <p>I can't seem to print this message. What am I missing? The POST works but the error response is showing blank...</p>