With little details to gone that will be harder for anyone to test if their system behaves the same.

What's your computer system and Firefox version?

Please explain the problem in detail. What happens? Error messages?

There is security software like Avast, Kaspersky, BitDefender and ESET that intercept secure connections and send their own certificate.

https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can

https://support.mozilla.org/en-US/kb/firefox-and-other-browsers-cant-load-websites

https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message

https://support.mozilla.org/en-US/kb/connection-untrusted-error-message

http://kb.mozillazine.org/Error_loading_websites

OSX and Windows, Firefox Quantum 57.0

well over 80% of the websites that we are trying to access don't load.

We get an orange lock symbol next to the address bar, when you select this to see more info it just states that the website is unsafe to open.

We have seen on some google searches that there should also be a way to turn off security features on the page that you are trying to access but none of the sites that we are trying to access have this option when we are clicking on the lock icon.

Have now spent the day removing Firefox from 127 PC's and Mac, have had to tell everyone to use Internet Explorer or Safari instead.

We have 2 test system, 1 Mac and 1 PC both with Quantum still installed and still no fix found.

James

Have you checked the links I posted?

Hi James, you have two largely identical threads going. I replied here:

https://support.mozilla.org/questions/1194014

Best is to concentrate the support to one question thread and the other one addresses already more subject, so I will close this question and please continue in your other question.

• [/questions/1194014]

You probably get that special icon because HTTP content is loaded on a secure HTTPS page. You can check the Web Console for more detail about what files are involved.

• https://developer.mozilla.org/en/Tools/Web_Console

Note that this can indicate that a website isn't meant to be accessed via a secure connection, but needs to be opened via an open HTTP connection.

You can see a special padlock at the left end of the location/address bar.

• a padlock with a strike through means that mixed active content is blocked.
• a padlock with an exclamation mark attached means that mixed passive content (e.g. images) is present, but not blocked.

The shield icon, previously used for mixed active content, is now used for Tracking Protection.

• https://support.mozilla.org/en-US/kb/mixed-content-blocking-firefox
• https://support.mozilla.org/en-US/kb/control-center-site-privacy-and-security-firefox

• https://developer.mozilla.org/Security/MixedContent