Recent answers to Insucure connection for 99% of websiteshttps://support.mozilla.org/en-US/questions/12459432019-01-06T15:16:47-08:00If you return to the "Advanced" section were you found the code
SEC_ERROR_UNKNOWN_ISSUER
Could you c2019-01-06T15:16:47-08:00jscher2000https://support.mozilla.org/en-US/questions/1245943#answer-1186804<p>If you return to the "Advanced" section were you found the code
</p><p>SEC_ERROR_UNKNOWN_ISSUER
</p><p>Could you click that code. Firefox should display a coded version of the certificate it can't verify. You can copy/paste that into a reply to see whether it helps identify a "man in the middle" causing this problem. Or you can paste it into a decoding page such as the following and look at the Issuer:
</p><p><a href="https://certlogik.com/decoder/" rel="nofollow">https://certlogik.com/decoder/</a>
</p>There is security software like Avast, Kaspersky,
BitDefender and ESET that intercept secure
connect2019-01-06T14:28:42-08:00fredmcd-hotmailhttps://support.mozilla.org/en-US/questions/1245943#answer-1186800<p>There is security software like Avast, Kaspersky,
BitDefender and ESET that intercept secure
connection certificates and send their own.
</p><p><a href="https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can" rel="nofollow">https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can</a>
</p><p><a href="https://support.mozilla.org/en-US/kb/firefox-and-other-browsers-cant-load-websites" rel="nofollow">https://support.mozilla.org/en-US/kb/firefox-and-other-browsers-cant-load-websites</a>
</p><p><a href="https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message" rel="nofollow">https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message</a>
</p><p><a href="https://support.mozilla.org/en-US/kb/connection-untrusted-error-message" rel="nofollow">https://support.mozilla.org/en-US/kb/connection-untrusted-error-message</a>
</p><p><a href="https://support.mozilla.org/en-US/kb/websites-dont-load-troubleshoot-and-fix-errors?redirectlocale=en-US&amp;redirectslug=Error+loading+web+sites" rel="nofollow">Websites don't load - troubleshoot and fix error messages</a>
</p><p><a href="http://kb.mozillazine.org/Error_loading_websites" rel="nofollow">http://kb.mozillazine.org/Error_loading_websites</a>
</p>