title: SignalR returns error - but how to find what it means $.connection.hub.error(function (err)
body: <p>The following alert is fired in my app, but JSON.stringify(err) is always "". Is there any way for me to understand what is triggering this exception? </p>
  
  <pre><code>            $.connection.hub.error(function (err) {
                  alert("Error signalR:" + JSON.stringify(err));
              });
  </code></pre>