Hello.
If you look at the other thread about this problem you will see a post by some at the Avast team who says that they had problems with their secure DNS server but that would have been solved. But unfortunally the message “secure DNS server can´t run on your network” is still there. I asked for a reply how to get rid of it. Hopefullly they will present a solution but I wouldn´t count on it. It´s all the same very frustrating because it makes me wonder if i´m fully protected despite the fact that it shows all green and says all sheilds are on and everything is updated.