On my app, the zWave dongle tile in the list of Smart Devices shows up with an empty circle of the left section, and in the right section, a greyed out wrench and 'in bold' UNKNOWN under the description of the device. Well, the zigbee GE 45856 switch shows up the same way, with empty circle, greyed out wrench, and UNKNOWN under the description of the device. So the app sees that it's there, but doesn't konw what it is and can't have a dialogue with it.
I closed down the app, rebooted the router, rebooted my phone ... all to no avail. The router sees it and can dialogue with it, but not the app. The analogy that comes to mind is a Parisian frenchman who cannot fully understand the regional country dialect of a frenchman from a far removed, backwater village.