What is the exact error messages?

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-error-message

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

Websites don't load - troubleshoot and fix error messages

http://kb.mozillazine.org/Error_loading_websites

Unable to connect

Firefox can’t establish a connection to the server at augmentinforce.50webs.com.

   The site could be temporarily unavailable or too busy. Try again in a few moments.
   If you are unable to load any pages, check your computer’s network connection.
   If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the Web.

I had no problem with the link.

Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

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

1- I followed every suggestion from the original reply's links with troubleshooting tips. Nothing helped.

2- I was able to visit ALL of my fav sites until about a week ago. Something has changed. Either I am shown that the site does not exist, as posted above in copy and paste post, or I am warned of certificate errors. Never had these troubles before. As the issue is new I would think something strange is happening.

3- Why in the world would I start Firefox in safe mode? Did I miss part of a convo??

Please list your Extensions as no information was supplied when you made this question, What Security Software are you using ?

You did not answer the question by Fred.

Yes you did, safe mode will determining if it is a Extension, please follow directions.

SAFE MODE

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

In Firefox Safe mode these changes are effective:

• all extensions are disabled (about:addons)
• default theme is used (no persona)
• userChrome.css and userContent.css are ignored (chrome folder)
• default toolbar layout is used (file: localstore-safe.rdf)
• Javascript JIT compilers are disabled (prefs: javascript.options.*jit)
• hardware acceleration is disabled (Options > Performance > Uncheck to view)
• plugins are not affected
• preferences are not affected

TEST''''is issue still there ?

I use Privacy Badger and HTTPS Everywhere.

I asked if I missed a convo as obviously I am not seeing all posts on my thread.

If I saw a question I would have answered it. No reason to be snippy, if you are in a poor mood perhaps don't bother with others online, just a suggestion.

TheSageCottage said

3- Why in the world would I start Firefox in safe mode? Did I miss part of a convo??

https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode

Safe Mode is a troubleshooting mode that temporarily turns off hardware acceleration, resets some settings, and disables add-ons (extensions and themes). If the problem goes away, that tells us one thing. If it does not, that tells us something else.

Note that HTTPS Everywhere can force secure connection on websites that do not have a certificate installed and this can produce a certificate error (you may see the certificate from the hosting company). In such a case you need to make an exception.

If you see it is a lot of cases then check the issuer of the certificate by clicking and Advanced button to expand the error message and then click the blue error code.

I was able to view all my fav sites using safe mode. I removed my add ons and then reinstalled and now all is well. Thanks for the help, appreciate it, good night to all.