The xcam is almost identical to the icamera2, with the exception of the wifi module being placed in the power supply adapter. The intent is to get better wifi reception by moving it inside the home and closer to the router. That also means you have to use the original power supply vs an aftermarket POE adapter if you want to retain wifi service.
The next thing that comes to mind is all of the icameras models disable wifi as soon as you plug in a hardwired ethernet source. That is why the icameras provide 2 POE dongle adapters. One is used for the initial hardwired provisioning of the camera and the 2nd dongle is used to provide power to the camera but no ethernet connection, thus allowing the wifi module to activate.
Did you setup the wifi login info on the xcam first and then disconnect the provisioning dongle and plug the Cat5 directly between the xcam and its power supply?