How was your FF update or installed?

I am on firefox quantum 6.0.2 64 bit. Firefox automatically updates. Installed when it became available. Have not reinstalled.

Do you also see the SEC_ERROR_UNKNOWN_ISSUER error message?

Try disabling SSL scanning in AVG/Avast.

I don’t use it, but depending on the AVG product, one may find the setting here (quoted from here and here):

"Open AVG Internet Security and click on Menu->Settings-> Components->Online shield->Customize->Main settings-> uncheck https scan"

"Open AVG and click "Options" -> "Advanced Settings" -> "Web Browsing Protection" -> "Online Shield" -> "Expert Settings" uncheck "Scan encrypted (TLS and SSL) network traffic" option."

Also and for Avast, see these support articles:
What do the security warning codes mean?
How to troubleshoot security error codes on secure websites.

I do get "SEC_ERROR_UNKNOWN_ISSUER error message" Once I get it on 1 website, it occurs from then on to all websites I try to get to .

I just uninstalled Avast and reinstalled AVG. Have been an AVG user for many years now.

There is a selection to "enable HTTPS scanning" on main settings. I have unchecked it. It will be a few days before I will know if this fixed it.

And I also run Malware bytes.

Sue

Hi, it is your AVG which is now owned by Avast. There is security software like Avast/AVG, 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

got my "Your connection is not secure" message again when trying to get to amazon.

I made the changes suggested in line 1. Will reboot and see if this fixes it.

Hi, you may have to go to the Community Forum or their Help site for info. https://support.avg.com/answers

You can check if there is more detail available about the issuer of the certificate.

• click the "Advanced" button show more detail
• click the blue SEC_ERROR_UNKNOWN_ISSUER message to show the certificate chain
• click "Copy text to clipboard" and paste the base64 certificate chain text in a reply

If clicking the SEC_ERROR_UNKNOWN_ISSUER text doesn't provide the certificate chain then try these steps to inspect the certificate.

• open the Server tab in the Certificate Manager
  • Options/Preferences -> Privacy & Security
    Certificates: View Certificates -> Servers: "Add Exception"
• paste the URL of the website (https://xxx.xxx) in it's Location field.

Let Firefox retrieve the certificate -> "Get Certificate"

• click the "View" button and inspect the certificate

You can see detail like the issuer of the certificate and intermediate certificates in the Details tab.

Got my "Your connection is not secure" message again. Not able to get to any website again. Made sure "no Proxy", network.dns.disableIPv6 to set its value to true, and network.dns.disablePrefetch Select true.

Will try the AVG group to see if anyone there has the problem, but a quick search did not come up with anything.

Back to Chrome.

Did you check if there is certificate information available?

Once the problem happens, its on every website I try to get to even this one. AVG has some suggestions to try, so waiting for the problem to occur again.

You can also check the date and time and time zone in the clock on your computer: (double) click the clock icon on the Windows Taskbar.

• https://support.mozilla.org/en-US/kb/what-does-your-connection-is-not-secure-mean
• https://support.mozilla.org/en-US/kb/troubleshoot-time-errors-secure-websites
• https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message

The problem appears to be with AVG right now. Had uninstalled AVG and was using Windows defender, AVG asked me to disable components one at a time to see if any change. Reinstalled AVG, 6 days later, got the error. When I disables "web" protection problem went away. When I re enabled all the components firefox was working. Avg has asked me to uninstall. Now using windows defender.

Sue

Hi Sue, thank you for the update. Usually it is a one-time process of setting up Firefox to work with the AVG/Avast web shield feature. It's puzzling that you keep running into the problem over and over.

If you decide to try the products again in the future, it could be worth exploring whether some other process on your system is clearing out files from your Firefox profile folder. In particular, the cert9.db file (in earlier versions, the cert8.db file) stores the signing certificate used by AVG/Avast for their fake website certificates. (Any "man in the middle" needs to create fake certificates to intercept your secure connections.) If there is some other process removing that file and breaking trust between Firefox and AVG/Avast, perhaps you can stop that from happening.

I have been using Windows defender since the 18th and have had no problems. Will reinstall AVG today. If I have the problem, I will first try to reset firefox. There has been a firefox update since I last had the problem.

Sue

Its been 4 weeks now and the problem has gone away, not sure what it was.

Sue

Hi, Great. Please mark your answer as the solution to the issue so others can find it.

Problem has gone away with updates to firefox and avg.

Solved