As previously reported, macOS and iOS now prioritise IPv6, this seems to be causing problems with the SmartHub. iPads and MacBooks when their IPv4 lease expires then get an IPv6 connection but no IPv4 connection from the router. This leaves them unable To connect. There is a manual workaround - allocate a fixed IP address and use Google as your DNS provider. This works but seems overkill and requires some networking knowledge.
Any idea when or if this will be fixed?
What hub are you using and what firmware version is it running? It's possible either DHCP or DNS is no longer working on the hub. I've seen the DNS server pack up on the Smart Hub in the past so no Internet addresses could be resolved.