Obviously, there are as many different types of Smart TV as there are reasons this problem could be happening, which makes it extremely difficult to diagnose. Given the popularity of ITV Hub, however, it’s far more likely to be a problem on your end.
If you haven’t already, try updating the app to its latest version and clearing the TV’s cache from the settings menu. You may also want to try disabling any active Smart DNS services to see if those were causing the issue. If you’re still struggling to stream ITV Hub, we recommend reaching out to your TV’s manufacturer via its online forums or asking your VPN service provider for help directly (assuming ITV works fine with the VPN disabled).