I'm new to this thread. I only started seeing the error message from: chrome-extension://pfbnibmoolhgbfipkfleejeebdhpmecl/data/ui/errorPage.html which reads:
"! Error The Norton extension for Chrome cannot communicate with the Norton Security application." I believe I have Norton 360 Premier. Am using MacBook Pro mid-2012, with OS Sierra 10.12.2 I think the problem began a few days ago, shortly after I enabled/turned on the Mac OS firewall. It had been off and I was relying on Norton's firewall. A week ago I downloaded Skype, had slowdowns and lockups, and offloaded it. Any ideas, please? And since I am a novice, if you identify certain extensions, I need directions where to find them. Please and thanks!