I recently upgraded to the Complete Wi-Fi package and have a shiny new Smart Hub 2. Earlier today it appeared to suddenly forget how to find a part of the internet. I was connected to my work VPN, able to log into various services and reach almost every site I desired, except my Bank was coming up with a blank page.
Same on my work PC and the mobile - unless I used mobile data in which case all was fine.
I restarted the router via the web GUI, no difference. After spending 10 minutes waiting for a chat person to be free, and a similar time on the phone I trotted off downstairs and rebooted the router with the button - counting to 10 before powering it back up. Hey presto service restored.