If someone knows a good AT&T routing problem contact, please let me know offline.
Apparently in some cases the AT&T system routers in the business fiber division stop routing IPv6 to customers.
I suspect some mid-level DHCPv6 larger block lease expiration issue, but all I know for sure is that AT&T mid-level routers start returning "address unreachable" errors for blocks of IPv6 addresses.

As expected there is no working customer service infrastructure at AT&T to deal with anything other than customer modem issues and they're not allowed to escalate.

If anyone has a contact, please let me know.

thanks,

Al Whaley
Sunnyside Computing, Inc.