I am running Firefox 67.0.4 (incremental updates) on Windows 10 Home version 1809 with Bitdefender free edition. When I create new profile in Firefox and open it in new window from about:profiles or when I open the new profile as solely instance with the profile manager, the browser can not connect to internet. No other browsers can open any web page afterwards. When I restart PC and start Firefox with my current default profile, all works without problem. I checked firewall settings in Windows, there are no changes after creating new profile and all browsers are allowed. I tried to use No proxy settings in Firefox, with no change in behavior. I tried to disable Bitdefender and then create new profile with the same result. When I start the new FF profile, no internet connection gets to any browser. Ping in command line has normal results though. I don't know where else to look.