Thought I'd add in something, I got the same message but the fix didn't work for the reason that it was the interface that was displaying that screen with the only option being a box to exit.
It occurred immediately after I ran the program update.
The issue is to do with OpenDNS of all things, on it's highest filter setting avast.com is blocked, adding it in as an exception, waited the obligatory 3 minutes and rebooted for it all to start working again.