Firefox 50.1.0 or any recent Releases itself does not have this issue.

There are a couple common reasons why Firefox cannot connect to https:// sites (especially on Windows). A long time cause has been due to Date/time being incorrectly set to a later date/time.

A common cause of late has been due to some antivirus clients trying to help you be safe by inserting its own certificate and instead can cause Firefox users to have trouble in connecting to https:// sites.

https://support.mozilla.org/en-US/kb/troubleshoot-SEC_ERROR_UNKNOWN_ISSUER#w_antivirus-products

I thought of that too. so I disabled all my Firefox add-ons as well as turning of my antivirus and it had no effect. I even reinstalled Firefox using Chrome since Firefox still won't display anything from Mozilla that has HTTPS. Is there a way to just force Firefox to ignore this error code.

It's just really annoying because all the so-called solutions on line just say to contact the Administrator of the Website because the problem is an issue on their end. But my issue is obviously something wrong with Firefox because it refuses to display any site that is HTTPS regardless of how many or which sites I try.

I may just backup all my bookmarks and do a fresh install and see if that works. This is just really frustrating because Firefox doesn't even give me an option to ignore the stupid warning and proceed, because "of my safety and security", and blames the websites for it. I use Firefox because of the fact that Mozilla places such a high regard on privacy but this is really irritating.

There should be a button with that Error message to ignore it and continue so people don't get stuck behind a wall like this. I've used Firefox for years but this is seriously making me rethink which browser should be my default.

Just turning off your unnamed antivirus may not do it as you need to change a setting or two as the article I linked to points out.

Hi again, I already did follow the steps from the article you linked before my previous post. My Antivirus is Kaspersky's by the way. I changed the settings under Network options as it suggests and restarted my computer just to make sure the change took. But I still had the same issue. That's why I was so irritated. Even after altering, disabling, or turning off anything that should/could have been causing the issue, it still didn't work.

So I decided to go ahead and backup my bookmarks and just do a fresh install. Now Firefox is working. My Kaspersky settings are back to what they usually are. I'm not sure what changed but a fresh download seems to have fixed whatever my problem was.

Thank you for your help. Sorry if I came off as impatient or rude, it's just been a less than perfect day. This problem was just the last straw. I do appreciate your assistance, and thank you again.