There is security software like Avast, Kaspersky, BitDefender and ESET that intercept secure connections and send their own certificate. Need to update and go to their forums for answers.

• 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
• http://kb.mozillazine.org/Error_loading_websites

Please let us know if this solved your issue or if need further assistance.

This is on linux mint. Ffox 57.0.4

I don't use any of those. I believe it started happening after upgrade to quantum.

Can you access the site with Firefox.

Pkshadow said

There is security software like Avast, Kaspersky, BitDefender and ESET that intercept secure connections and send their own certificate. Need to update and go to their forums for answers.

• 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
• http://kb.mozillazine.org/Error_loading_websites

Please let us know if this solved your issue or if need further assistance.

Is that the only website where this happens?

You can try these steps in case of issues with web pages:

You can reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.

• hold down the Shift key and left-click the Reload button
• press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• press "Command + Shift + R" (Mac)

Clear the cache and remove the cookies from websites that cause problems via the "3-bar" Firefox menu button (Options/Preferences).

"Clear the cache:

• Options/Preferences -> Privacy & Security -> Cached Web Content: "Clear Now"

"Remove the cookies" from websites that cause problems.

• Options/Preferences -> Privacy & Security -> "Use custom settings for history" -> Cookies: "Show Cookies"

If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block (wanted) content (e.g. Adblock Plus, NoScript, Ghostery, uBlock Origin) always make sure such extensions do not block (wanted) content.

• make sure your extensions and filters are updated to the latest version

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Try to disable IPv6 (check for other possible causes as well).

• https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can

cor-el said

Is that the only website where this happens? You can try these steps in case of issues with web pages: You can reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.

• hold down the Shift key and left-click the Reload button
• press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• press "Command + Shift + R" (Mac)

Clear the cache and remove the cookies from websites that cause problems via the "3-bar" Firefox menu button (Options/Preferences). "Clear the cache:

• Options/Preferences -> Privacy & Security -> Cached Web Content: "Clear Now"

"Remove the cookies" from websites that cause problems.

• Options/Preferences -> Privacy & Security -> "Use custom settings for history" -> Cookies: "Show Cookies"

If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block (wanted) content (e.g. Adblock Plus, NoScript, Ghostery, uBlock Origin) always make sure such extensions do not block (wanted) content.

• make sure your extensions and filters are updated to the latest version

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Try to disable IPv6 (check for other possible causes as well).

• https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can

thanks so much for responding.

It's the only site where I encountered this.

I tried refreshing with shift reload and ctrl f5

I had already tried clearing cache. I use "never remember history" so there are no cookies

I do use uBlock, however the same thing happens in safe mode.

I am running in Defaullt appearance

Disabling IPv6 makes no difference.

I clicked on the same site in FF57.0.4 and got there without any problems. I only have W10 Defender/Firewall. So I think you got other problems going on and it isn't a W10 nor FF problem.

What NS service are you using? Does it work with Google in case the service you currently use isn't working?

See also DNS:

• http://kb.mozillazine.org/error_loading_websites

You can test the DNS lookup via the DNS tool on the about:networking page. You can open "about:" pages via the location/address bar

• "about:" is a protocol to access special pages

It turns out it was not a FF issue, but a strange DNS situation just for that site.