Found this piece of advice
Factory reset the now TV box - leave it to reset, leave it on and plugged in with TV on.
Go to your BT Home Hub and router - turn them both off at the mains, wait 30 seconds
Turn the power back on to the router
When all the lights are blue on the router (Power, Wireless and Broadband) go back to the Now TV box.
Use the secret wifi screen easter egg ( press home X5 then quickly press FF, Play, Rewind, Play FF, just once each)
When the secret wifi screen is displayed make sure it says Network Ping Disabled.
Go back and then start the configuration process to connect to wifi and then log into your Now TV account.
Of cause it could be a faulty now TV box