FIREWALL ISSUE FIXED IF YOU HAVE NORTON ANTI VIRUS!

[shrimb]

If you're running Norton Antivirus, check your settings for your games. This can be done by going to Settings > Network Tab > Smart Firewall > Program Rules > Change what ever game you want to fix from "Block" to "Allow". That seemed to fix the #cef error for me.
This new steam update goes for your firewall. I have no clue why. I hope this helps some of you with the same error I had!