Posting in what is an extremely old topic won’t really help much will have changed in over two and a half years.

You would have been better to have created your own new topic and given more detailed information.

You don’t even say what Avast Program and version/build number you are running ?

I have no idea what topics about the avast firewall (or even if you have an avast program with the avast firewall) you have read. But one of the easiest checks you could have made was to ensure the avast firewall mode was set to private.