Chromecast "Connected to BTHubXX, cannot connect to internet" BTHH5 SOLUTION
I have been trying to get my Chromecast to work with my BT HH5 for about 3 hours now.. finally jagged a solution, thought I should share it incase anyone else was also pulling their hair out.
Log into your BT HH5 by opening your web browser on a device connected to the Hub and go to bthomehub.home. This will open the Hub Manager. Go to the Advanced Settings (your login details should be on the card in the router).
Rename your SSID by following the instructions here:
Switch off Smart Setup (under Advanced Settings/Home Network/Smart Setup)
Change your Firewall settings to disabled (under Advanced Settings/Firewall/Configuration)
I recommend changing these back after the ChromeCast has configured
Turn off UPnP (under Advanced Settings/Firewall/UPnP)
Unplug the USB power to the ChromeCast and restart your BT hub. Wait for your router to come back online, then plug in your ChromeCast. Using the ChromeCast app, follow the setup steps onscreen.. hopefully your ChromeCast will be able to access the internet and update its firmware!
Don't forget to go back to your Firewall settings and turn the Default back on after the ChromeCast has finished updating!