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

https://support.mozilla.org/en-US/kb/what-does-your-connection-is-not-secure-mean

Often, "Secure Connection Failed" means "Connection Failed (trying to load a secure page)". In other words, not a security problem, just a connection problem.

Thanks for trying to help FredMcD :-)

As stated in my original Message though, I have tried disabling Avast Anti Virus by temporarily turning off the "Web Shield", and also running it in "Passive Mode" where "Real Time Protection" is turned off, and these make no difference.

Unless there is another setting in Avast that needs to be changed ?

( Though I dont know why unless somethign as been changed in any recent update to Avast that I'm not aware of ? ).

Also as stated, the Page will open correctly using Chrome Browser - when Avast Anti Virus is running. ?

I'm at a loss with this !

Thanks.

Make sure you are not blocking content.

Start Firefox in Safe Mode {web link}

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

https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop

Tried that - still exactly the same after restarting Firefox in Safe Mode.

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

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode Starting Any Computer In Safe Mode; Free Online Encyclopedia

Just tried this - Windows 8.1 PC restarted in Safe Mode ( "Safe Mode" displayed in each corner of the Desktop screen ).

Tried the web site again - still the same error message !

Just to add that I wasn't sure exactly what you meant by, "Try Secure websites."

The Web site I am trying to access IS a Secure website ( https ).

Other Secure Web sites open with no issues.

Thanks.

I called for more help.

FredMcD said

https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop

Hello Alan,

Did you turn Enhanced Tracking Protection off to see if that will make a difference ?

(it's the shield icon next to the padlock)

I haven't tried that previously, but just did - and it makes no difference.

Hi Alan M

I have no problems accessing this lottery website with Firefox 75 and two Windows 10 computers using Microsoft's built-in antivirus software.

I suggest uninstalling Avast. Disabling Avast isn't enough for it to stop blocking Firefox.

If that doesn't work then scan for malware using software like malwarebytes.

Hope that helps move things forward! Cheers! ..Roland

Thanks Roland,

Before I try your suggestion of uninstalling Avast - which would obviously leave my PC completely unprotected, it would be remiss of me not to ask : If Avast IS the cause of this problem, why does using a different Browser, such as Chrome, on the same PC, with Avast running, allow the Page to load without any problems ?

Meanwhile I will try running Malwarebytes as suggested.

Thanks

Further to my orevuosu reply, I have just run Malwarebytes.

It did find ( onkly ) one "Potentially Unwanted Program" that I Quarantined : "PUP.Optional.ForcedInstalledExtensionFF, C:\USERS\USER\APPDATA\ROAMING\MOZILLA\FIREFOX\PROFILES\JJLYZ4WM.DEFAULT\EXTENSIONS\[email protected], No Action By User, 1796, 674581, 1.0.22758, , ame,"

This has made no difference at all, so I'm just awaiting a reply about the Avast suggestion before trying that.

Thanks.

Before I try your suggestion of uninstalling Avast - which would obviously leave my PC completely unprotected,

Would you please go over   these search results .....     ?

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

As a personal note :   you're best off with just using Windows built-in security software.

Also see :

https://www.howtogeek.com/239950/dont-use-your-antivirus-browser-extensions-they-can-actually-make-you-less-safe/

And :

http://tech.firstpost.com/news-analysis/ex-mozilla-firefox-developer-says-anti-virus-software-does-more-harm-than-good-359798.html

Those pages listing lots of different Anti Virus software products, and Links suggesting reasons for not using them, still don't answer the question, or fix the problem of why I can't load this particular Page with Firefox, but I can with other Browsers on the same PC using the same Anti Virus program, and why I used to be abel to load the oage in Firefox, but now I can't.

While it is interesting read about how WIndows Defender and the Security features of Firefox "should" be all that is needed to protect my PC, it is a fact that Avast HAS caught malicious pages in the past and Blocked access to them, and I simply don't know whether Firefox or Defender would have done so if Avast hadn't been running.

I DON'T have any Avast add-Ons or extensions running in Firefox.

My post was a reaction to your :

"which would obviously leave my PC completely unprotected "

Merely meant to reassure you;   set your mind at ease ......

That didn't work either ! LOL !

Thanks.

That didn't work either ! LOL !
Thanks.

At least one positive thing came out of my post :   I made you laugh !

But all kidding aside :

I sure hope that someone will come up with the perfect solution for you !

OK, so I had a think, and I thought, I will try uninstalling Avast as recommended and reassured, on the grounds that I could quickly check if the Page would now load, and if not I could always "simply" re instal Avast again - right ? No warnings issued about anything that might go wrong - right ? WRONG !

I uninstalled Avast and on Restart got a message saying Windows Defender was disabled, and needed to be started, so I followed the prompts to do that which resulted in another re-boot and then the PC would NOT start up at all, being stuck on the "Please wait" Spinning wheel of doom for over half an hour.

MAJOR PANIC thinking my PC was now fried, and I wouldn't have access to loads of files that hadn't yet been backed up etc.

Fired up a very old Windows Vista laptop that is also running Avast Anti Virus, to update this message and search for "How to boot up a Windows 8 PC that doesn't want to play", and the "troublesome" page loads up perfectly ! !

After 3 forced shutdowns and restarts my Windows 8 PC eventually booted back up again but Windows Defender was still not running. From the Action Centre I clicked "Start Now" and it seemed to work, but now reported the latest Virus definitions and Spyware needed to be updated, so I followed the process to do that.

After all the files were eventually downloaded, I started Firefox again and tried the Web page.

STILL THE (censored) SAME - None of these suggestions have made any difference at all other than to leave me with loads of stress and fewer hairs on my head after pulling most of them out !

So I'm giving up / quitting and will be gradually switching my Bookmarks over from Firefox to Chrome, then binning Firefox altogether as, from my perspective, there is something seriously wrong with it that has done something to my PC that not even the experts in here ( who I thank for at least trying ) have been able to help with :-(

I am so, so sorry you had to go through all of that trouble   (understatement).

But please,   don't give up on Firefox just yet and wait for someone   (who may
be asleep right now)   to come to your rescue.

Will you do that ?

There just   has   to be an explanation,   and most of all :   a solution !