I have found that Firefox loads normally with most sites but now, some only load the HTML code associated with those sites and the actual page doesn't open. With my Chase banking site, I can open the site but I get the HTML code when I try to log in. I have also found this happening with certain Meetup group sites and someone's facebook page.
My version of firefox is up-to-date and I am using MacAfee as my Antivirus software on a Windows 10 system. I can open these sites normally with Chrome.
Not sure what the issue is or what to do about it. I'm wondering if there is certain incompatibilities resident in the most recent Firefox version.