when i connect my xbox one via wireless it works fine but wireless speed jumps up and down between 3mbps up to 31mbps. if i connect via ethanet to get a more stable connection its just says can not connect i have tryed changing the IPv4 setting on the xbox to what my router says but it still wont connect,
What about switching off the NOW Broadband Buddy on your NOW online account if you can't access the Xbox servers ?
I don't own an Xbox so i won't be much further help sorry (hopefully an Xbox One owner using NOW Broadband will come to your aid).
Should nobody comes to your rescue, then see if the NOW Broadband Team can assist you further.
Use the telephone number in this link (they close at 8pm so maybe give them a call tomorrow morning after 8am).
I would be also tempted to try a Google search by typing "Xbox One won't connect over Ethernet on Sky Q Hub Router" ( where the Sky Q Router is a clone of the NOW Hub 2).