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

What do the security warning codes mean

I still don't get it, works find on other computers, but not on my main desktop, its odd.

Did you check out my last post?

I can see all the links and security software thing you mentioned, but i don't understand how that can do anything, not sure exactly what you mean

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Go to that message, and use the Undo link to its right.

You can check details about the issuer of the certificate and the certificate chain.

• click the "Advanced" button on the error page to show more detail

You can possibly paste the base64 encoded certificate data in a reply. You can click the blue "View Certificate" text to inspect the certificate chain in the Certificate Viewer in a new tab.

I can't see that either, sorry? I have a valid certificate. This is one message i get..... This page isn’t working www.lockmonster.co.uk didn’t send any data. ERR_EMPTY_RESPONSE

https://www.bing.com/search?q=ERR_EMPTY_RESPONSE

Among the links is: You may have ad/mal-ware. Further information can be found in this article; https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware?cache=no

Run most or all of the listed free to use malware scanners. Each works differently. If one program misses something, another may pick it up.

I'll run the windows 10 malware first, Thanks

Hello Info,

It's always a curious thing when something works ok on one machine but not on another.

So its always a good idea to go to the dysfunctional machine and peel away the layers of the onion in order to see what the root cause is for the dysfunction.

As Fred mentioned, there are security software that could be blocking the site. I think temporarily disabling them and seeing if the issue is resolved would be a good clue for you.

However, you can achieve the same effect by launching your windows in safemode w/networking.

Let us know what you discover.

btw: your bitdefender is likely the problem here.

I'm running a scan now with bitdefender, is it not great?

hello info

i have seen a number of posts where bit defender has been the cause.

i dont use bit defender. so maybe it needs to be configured or updated or something.

so bottom line is, if you want to drill down to the cause(s) of the issue, you must eliminate (disable) all the possibilities - at least temporarily.

so the entire mozilla world wide technicians are asking you to temporarily disable all your a.v.'s, cookie scanners, cleaners, etc.., for now.

if the issue goes away, ie no longer exists, then you can enable each application one at a time to see which one is posing a conflict.

Guess what, I deleted bitdefender, it's fine now, I'll just use the windows 10 firewall and protection that come with the desktop I think. Thanks for all your help.

Great job!

now, here's a couple of suggestions:

1) set your "enhanced tracking protection" to "strict". Paste and go to

about:preferences#privacy

Later if you experience issues, you can use the options there.

2) install an app called Privacy Badger. It is a good app and very informative.

3) Have fun with FireFox !!