Is firewall network profile in puplic or private mode?
If not already done try private and reboot
Setting up Firewall Application Rules in Avast Antivirushttps://support.avast.com/en-eu/article/Antivirus-Firewall-Application-Rules=================================================================
NOTE:The Network profiles control the settings which determine how strictly Firewall protects your PC.
Private: a lower level of security suitable for when your PC is connected to a trusted network such as your home or work network.
This profile enables better connectivity,
and permits all communication within the network.
Public: a higher level of security suitable for when your PC is connected to a public network such as in a cafe or airport.
Because public networks present greater security risks,
no incoming communication is permitted when this profile is set.=================================================================
