To expand on ozsat's answer - your internet may well be fine on other devices but if it's been recently changed, and your V6 is connected wirelessly rather than an Ethernet cable, then it won't know the new wireless details.
Not knowing that, means your V6 doesn't have a working internet connection and you'll find OnDemand also won't be working.
Following Home > Help & Settings > Settings > Network is the place to fix it. Using an Ethernet cable if possible, will avoid this issue and also give your V6 a more stable connection.
I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more
Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks