I don't believe this is to do with your firewall as such, but an internal problem with the AvastUI.
The ? is just a context help function to to give relevant help information for the page you are on. I thought (always dangerous to think) this was from a local help file so it wouldn't need to connect. If I click on it from the main avastUI page this is what I see, attached image.
You could try an avast Repair.
