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

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-firefox-did-not-connect

https://support.mozilla.org/en-US/kb/websites-dont-load-troubleshoot-and-fix-errors

What do the security warning codes mean

The problem is getting worse, now not only .gov sites show same error message, my e-mail links to sites from my Thunderbird account produce the same error message. I tried typing in a different search site in the site bar and get the same message. I'm using Vipre security it's up to date. If I use Windows Edge no problem with anything. It all went to hell with the latest Firefox update. If I don't get any real help soon I will after years of Mozilla software use have to find a different browser that works and provides real support, other telling me to read a pile of reference links that I do not have any idea what the hell they mean.

I've kept my updates maintained for all my software, I read one link that should I return to using Windows Defender, if this is the logic of user support, I might as well start using Windows Edge, and uninstall Firefox.

So if some can walk me through correcting this problem, I'm all ears. Any takers?

Start Firefox using Troubleshoot(Safe) Mode {web link}

A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh). Is the problem still there?

Start your Computer in safe mode with network support. Then start Firefox. Try Secure websites. Is the problem still there?

Starting Any Computer In Safe Mode (web link) Free Online Encyclopedia

https://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/

https://www.digitalcitizen.life/4-ways-boot-safe-mode-windows-10/ +++++++++++++++++++++++++++++++++++++++++++++++ If the problem goes away with the computer in Safe Mode, the problem is with one of the other programs on the system.

As a test, disable your protection programs.

I disabled Vipre and turned Windows Defender and firewall. Everything seems to work for now. So I take it I should contact Vipre about the Firefox update conflict as Mozilla doesn't plan on any patches or updates to resolve this problem, correct?

I don't know about any Firefox updates. But, yes. Contact Vipre support.

Fred, Thanks for the help. If I can't resolve the conflict problem between Vipre and Firefox, is there a list of after market antivirus/firewall software that are compatible with the current Firefox, before I shell out green stamps on a replacement or am I stuck with using Windows Defender?

There are several that are free to use (for a limited time). see about one of those. Norton, Macafee . . .