I think Avast's server is down at the moment. I'm seeing the same issue.
Some more info:
The error refers to the URL
http://v0831702.ivps9x.u.avast.comWhen I ping "avast.com", I get a quick response. When I ping "u.avast.com", however, I get no response at all other than "Ping request could not find host u.avast.com". So it's not their entire domain that's down, just this one subdomain.
Unfortunately, I see no way other than this forum to alert them to their server being down. I don't like feeling unprotected.
Hopefully they'll realize their server's not working and fix it soon.