Was pleased to stumble upon this trail as it explains a lot.
I'm also a BT Infinity Hub3 user in portishead and every couple of weeks everything using https grinds to a halt.
I find that just rebooting the white openreach modem is enough to fix it.
I try to avoid rebooting the hub as re-connection is a bit hit an miss and can waste me an hour.
I see l someone has opened a tech call several months ago, but clearly it is still not resolved.
This is the same issue that others have reported on a number of other threads include unable to access ebay and an issue I believe with the Thomas Cook web site.
All the people find that resetting the WiFi hub forces a new IP address allocation and the site returns. We are trying to work out if it is a DNS issue or a specific router in the network.
I did a trace route before and after when it happened to me today...you can find it on this post:
If you get the same thing try to capture the before an after and we can narrow down the issue.
Another side effect of rebooting the OR modem is that it could be mistaken for a line fault at the exchange which can mess up the line profile.
Just thought I would mention it as there are lots of threads where people are trying to get thier profiles reset.
OK, can confirm Openreach Modem is culprit, rebooting router, didnt fix, rebboting modem did fix it.
I'm off to Drayteck for realiable hardware, so HH3 LAN ports hopeless and Modem block odd sites and needs a reboot, not great BT