I'm a web developer that setup a local environment under Linux Mint. For some reason, Firefox Developer Edition (59.0b7 64-bit) cannot access sites on my localhost. The interesting thing is that Firefox Quantum 58.0.1 (64-bit) is showing these local sites perfectly fine. I've tested other browsers, including Konqueror and Lynx, and these work fine also. I've setup my environment so that apache2 can serve pages from a 'wildcard' virtual host. Using symlinks, I can link my project files to another directory that functions as the web root. Thus: /home/me/business/projects/client/index.html => /home/me/business/www/client/index.html Navigating to http://client.dev brings up the page perfectly in Firefox 58, Konqueror, and Lynx. However, Firefox Developer Edition, AND Google Chrome, both fail to load the page. The URL changes from http://client.dev to https://client.dev and throws this message: "Unable to connect Firefox can’t establish a connection to the server at client.dev." I've played around with the about:config settings for Network.dns.* but nothing seems to help. Also, the apache logs do not produce anything useful. Your input will be greatly appreciated.