I have my own web server, and suddenly I can only access the site with HTTPS from Firefox on my home PC. I have tried adjusting the autofill settings clearing cache, even added a link on the page to click and load it as HTTP instead. Nothing works it always comes up with HTTPS. The page does load with Firefox on other machines as HTTP. So I suspect that at some point an error page loaded with a secure transport header in it (perhaps while doing maintenance on my firewall with uses NAT reflection to direct local machines to the web server) and Firefox has cached that in some method that it is not letting me clear it. I appreciate that there is some effort going into making the web more secure. But the site contains nothing that requires security and being the sites maintainer I need to be able to test it with both HTTP and HTTPS.