QBluetoothServer not working with QCoreApplication

I'm trying to build a simple Qt based echo Bluetooth Server (rfcomm).
I've noticed that when I'm using QCoreApplication(this is what I need because it will run on a board without display) instead of QGuiApplication or QApplication, I'm not able to receive any message and I'm not notified when a client is connected (SLOTS are not called).
*The entire code can be found here: http://pastebin.com/aU13zgw0
The server can be tested with Qt Bluetooth Chat example and the entire code of my server is extracted from the example.
It could be something related to the event loop but I don't know what.
I'm running the server on OS X El Capitan with Qt 5.6.1, Qt 5.6.0 and Qt 5.2.1.