Which Avast product do you have Free or Premium, also which Firewall i.e. Avast Firewall, Windows Firewall or other?
I have done a search here on the forum/community and found this from an old Beta release note for 20.7.2421 (build 20.7.5509), so was maybe a problem in the past, but I have no seen no other reports of icarus v firewall issues recently: