title: I can not authorize to hitbtc api from c#
body: <p>my code is:</p>
  
  <pre><code>HitBtcApi.HitBtcApi hitbtc = new HitBtcApi.HitBtcApi();
  hitbtc.Authorize("xxx", "xxx");            
  RestRequest request2 = new RestRequest("/api/2/account/balance", method.GET);
  var x= await hitbtc.Execute(request2, true);    
  MessageBox.Show(x.content.ToString());
  </code></pre>
  
  <p>this error rising when running:
  {"error":{"code":1001,"message":"Authorization required","description":""}} but when i use "/api/2/public/symbol" instead of "/api/2/account/balance" it work. please help me. thanks.</p>