I had a similar problem a while back when I was with still with sky and using sky fibre on the Ps4. I deleted the app also deleted any saved sky go data on the Ps4. Downloaded again and it worked. Have you tried that already?
Never had anything to do with Sky or Play stations either but a web search turns up loads of hints on managing Sky Go.
To get you started:-
Something else you might try if all else fails. Back up all your PS4 data to an external drive and do a factory reset of the PS4. Then you can start again with the Sky Go with a clean slate, so to speak.
Have you tried a factory reset of the Hub yet? It may clear up when you get a new IP address after the Hub restarts.