avast block internet access
What avast version do you have avast free/Pro/Suite/Premium ?
Avast doesn’t block, but alerts to infection.
What is your operating system and firewall ?
I have the same problem with avast internet security! After update I can’t access network, firewall is not running, manual start failed. After avast uninstallation still the same - no access to network. Avastclear in safe mode didn’t help. New avast installation is not possible - not trusted by self defense module.