Connected Devices Not Appearing

So I have 2 different Xbox Ones connected to my home wifi, and one of them appears on my Xfi connected Devices. However, the second is nowhere to be seen. It is indeed connected to the internet, and can use it no problem. But it just does not show on the Connected Devices. This means that I cannot pause the device if I needed to. It is quite infuriating.

I have restarted the modem, forgot the network on the affected xbox and reconnected, everything I know how to do to try and get it to appear. It is not appearing. 

Can SOMEONE help me get this xbox to appear?