When the Avast Firewall is blocking your application, you can enable Avast’s firewall logging tool to then identify the necessary exclusions.
Start by opening the Avast UI on the client and navigating to Protection > Firewall:
Next, navigate to Settings (Firewall settings, and not the Avast client setting)
Choose Advanced, and place a check mark in the “Log all blocked packets box”.
Next, click the OK button to return to the previous page, and then select “Firewall logs”:
You can then customize the parameters of the blocked logs report from there:
Please let me know what I can do to help, and have a great day!