Do you still have firewall rules? Check both firewalls, of AIS and of Windows (even if they are inactive, the rules are still present). Delete the firewall rules. Reboot and wait at least about 10 minutes after the reboot and review the update info in avast → maintenance → update → last attempt and definitions date.

Did as instructed, waited half an hour. No change

Was a new computer this spring. Never has had anything else installed except AIS

Will try safe mode method tomorrow. Something is stopping this system from calling home