My broadband has recently been upgraded from BT Infinity 2 with a BT Smart Hub to BT Full Fibre with a BT Smart Hub 2. Since the upgrade all devices appear to be working normally with the exception of the kids xbox consoles which can no longer connect to Xbox live and as a result the kids cannot play their games. Both xbox consoles are hardwired to the network are a connect to the router using tp-link powerline adaptors. The Xbox DNS settings have also been updated to use the google DNS servers (188.8.131.52 and 184.108.40.206) due to previous connectivity problems with the SM1. I've tried connecting the Xbox consoles to the internet using the wifi hotspot on my mobile phone and everything worked correctly, so the Xbox consoles themselves are fine. I've also tried connecting the consoles to the SM2 wifi network, but this also does not work either.
I'm now at a loss on what to do next. BT technical support suggested contacting Xbox support as, from their point of view, the internet connection is fine. But I suspect that the issue is actually with the SM2 router.
Any help would be appreciated.