Try downloading from; Download Firefox For All languages And Systems {web link}

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

‘ssl_error_rx_record_too_long’ or ‘cannot display the webpage’ Internet search; More often than not, you have something misconfigured!

Thank you, I appreciate your help :)

Can you suggest what might be misconfigured to cause these error messages? I use ZoneAlarm for firewall and anti-virus, plus of course McAfee, which was so helpfully included in the OS and that I haven't uninstalled yet.

Many thanks

Start Firefox in Safe Mode {web link}

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

Someone named "Philip" answered this question but it didn't work. In addition to what other people have reported, "An error occurred during a connection to download-installer.cdn.mozilla.net. SSL received a record that exceeded the maximum permissible length. Error code: SSL_ERROR_RX_RECORD_TOO_LONG" I also get: "The page you are trying to view cannot be shown because an error in the network protocol was detected."

Philip suggested Zonealarm may not be configured properly but I changed it & still get the error.

I just changed my Windows from using IPv6 to IPv4 because 6 was causing problems with another program I use. Could that be the cause?

Thank you all for your help. Firefox did eventually install version 65.0.1 64 bit itself and it seemed to be working ok, then this morning the shortcut had disappeared from the desktop.

When I started the program again, I had a new problem that I should probably put in another thread (and will do) but thought I'd mention it here as well:

Widevine has not installed and on the Add-ons page it says that it "will be installed shortly" but of course it hasn't been! That means I can't watch any DRM material, which is apparently most of the videos on the internet.

I've been using Windows for too many years and Windows 10 is the most problematic of all of them. I've never had so many issues with a new system!

I had this problem. I also use Zonealarm. I unchecked a check mark that allowed IPv6, that fixed it. Go figure.

Fixed problem.

So you now have the current Firefox? That was very good work. Well done. Please flag your last post as Solved Problem so others will know.

I do, but I don't know how I managed it! :D Thank you all for your help.

In order to get widevine to install on the new version, I had to rename my hosts file - and in order to do THAT I had to take ownership of it and remove the lock that ZoneAlarm had on it. Quite ridiculous really that the whole thing was so difficult.

As long as it's fixed. Check with ZoneAlarm support on this.

Try to toggle DRM off/on to see if that makes Firefox (re)load DRM components.

• Options/Preferences -> General: Play DRM
• https://support.mozilla.org/en-US/kb/enable-drm

cor-el apparently the issue was the hosts file (even though there are no active entries in it). I had to temporarily remove/rename it, which meant removing the lock on it first in Zone Alarm, which was easy enough once I realised where it was. As soon as I did that and refreshed Firefox add-ons, Widevine installed immediately.