There is security software like Avast, Kaspersky, BitDefender and ESET that intercept secure connections and send their own certificate.

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

https://www.bing.com/search?q=web+site+access+denied

I tried all those solutions. They didn't work.

narbilistic said

Your connection is not secure. Advanced-> Peer’s Certificate has expired. It happened all of a sudden to every website I visit. But Chrome works for me.

Check your system date and time on Windows to be sure.

https://support.mozilla.org/en-US/kb/troubleshoot-time-errors-secure-websites

James said

narbilistic said

Your connection is not secure. Advanced-> Peer’s Certificate has expired. It happened all of a sudden to every website I visit. But Chrome works for me.

Check your system date and time on Windows to be sure.

https://support.mozilla.org/en-US/kb/troubleshoot-time-errors-secure-websites

Tried all those already and checked the time too.

FredMcD said

There is security software like Avast, Kaspersky, BitDefender and ESET that intercept secure connections and send their own certificate. 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 https://www.bing.com/search?q=web+site+access+denied

Tried all those including, reinstalling Avast and disabling it. Tried reinstalling Firefox too.

Hi narbilistic, does anything happen when you click the ERROR_CODE on the Advanced page? When everything is working well, it should open a panel with certificate information. The encoded certificate looks like a large block of gibberish. If you see that, please click the button to copy it and then paste it into a reply. Then we can decode the certificate and get a better idea of what's going on.

If you do not get a large block of gibberish when clicking that link, you may need to investigate using a different site that is a little less strict with its security. For example:

https://www.userchrome.org/

Do you get the error there?

Assuming so: click the Advanced button, then click the "Add Exception" button (see first screenshot below). We're not really going to add an exception, but we can get a better view of the certificate here.

In the Add Exception dialog, click the "View" button to pop up a certificate viewer. The interesting part is the "Issued by" section. I've marked that on the second screenshot for reference.

On my site, the "Issued by" section shows me "Let's Encrypt Authority X3". What do you see there?

(These example screenshots are from a test page, not my site)

jscher2000 said

Hi narbilistic, does anything happen when you click the ERROR_CODE on the Advanced page? When everything is working well, it should open a panel with certificate information. The encoded certificate looks like a large block of gibberish. If you see that, please click the button to copy it and then paste it into a reply. Then we can decode the certificate and get a better idea of what's going on. If you do not get a large block of gibberish when clicking that link, you may need to investigate using a different site that is a little less strict with its security. For example: https://www.userchrome.org/ Do you get the error there? Assuming so: click the Advanced button, then click the "Add Exception" button (see first screenshot below). We're not really going to add an exception, but we can get a better view of the certificate here. In the Add Exception dialog, click the "View" button to pop up a certificate viewer. The interesting part is the "Issued by" section. I've marked that on the second screenshot for reference. On my site, the "Issued by" section shows me "Let's Encrypt Authority X3". What do you see there? (These example screenshots are from a test page, not my site)

Other websites like gmail, google, facebook; the "Peer's Certificate has expired" message isn't clickable.

But when I go to https://www.userchrome.org/, "Peer's Certificate has expired" has a Add Exception button but when I click it nothing happens.

Could you look one more place before we resort to brute force... Open Firefox's Network Monitor in the lower part of the tab. Either:

You could check for messages in Firefox's Web Console. You can open the Web Console in the lower part of the tab using either:

• (Windows) Ctrl+Shift+e
• "3-bar" menu button > Web Developer > Network
• (menu bar) Tools > Web Developer > Network

Then reload the page in the upper part of the tab and at least one request should appear on the list. Click that first request and on the right side, change to the Security panel. This may not be visible, so look for a little triangle at the end of the row with Headers, Cookies, etc. to switch to that panel.

Does Firefox show certificate information there?

jscher2000 said

Could you look one more place before we resort to brute force... Open Firefox's Network Monitor in the lower part of the tab. Either: You could check for messages in Firefox's Web Console. You can open the Web Console in the lower part of the tab using either:

• (Windows) Ctrl+Shift+e
• "3-bar" menu button > Web Developer > Network
• (menu bar) Tools > Web Developer > Network

Then reload the page in the upper part of the tab and at least one request should appear on the list. Click that first request and on the right side, change to the Security panel. This may not be visible, so look for a little triangle at the end of the row with Headers, Cookies, etc. to switch to that panel. Does Firefox show certificate information there?

for some reason it fixed itself... thanks !

All of a sudden it fixed itself today. Thanks guys!