Firefox, specifically the Windows version, has started generating PR_END_OF_FILE_ERROR errors on https:// web sites. What I find interesting is that Firefox says the page is not secure in the address bar - even though the page is secure. Firefox on Mac and IOS do not have this issue. I'm also running Bitdefender Anti-virus with Encrypted Web scan. With that feature turned off, blocked pages seem to work. I found yesterday that logging out of Sync while Encrypted Web scan is on allowed the blocked pages to load. I deleted Firefox and re-installed it, thinking I'd fixed the problem. No such luck. I've tried all the other fixes I can find but none of them work. This is clearly a Firefox issue and not an issue with Bit Defender since it only occurs (and has been widely reported for years) with Firefox for Windows. On a side note, even support.mozilla.org gets blocked. Anyone have a real fix that will work?