I set one up for a friend a while ago and had a similar problem.
I followed the procedure on page 44 of the installation guide & it magically started working :
"Try restarting your Hub and YouView box (and Openreach modem if you
have BT Infinity). Press the Restart button on the Hub and wait a few
minutes for the Broadband light to glow blue or green. Switch OFF the
power supply to the YouView box and then switch it back ON. If you have an
Openreach modem, turn it OFF, wait a moment, then turn it ON again"
Dave x