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Brand new installation and Firefox will not open ANY https:// web site

  • 3 replies
  • 6 have this problem
  • 494 views
  • Last reply by FredMcD

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Brand new computer. iMac. OS 10.12.6 (16G1212)

Dowloaded latest version from Mozilla website. Absolutely NO website that is https:// secured will open and that includes https://support.mozilla.org. Error states Mozilla (or whomever) has misconfigured their web site and it is not secure. Security unknown.

Help please?

Chosen solution

Problem resolved but all info regarding Avast is wrong and should be updated. Still enough to figure out a fix, Thanks

Read this answer in context 👍 0

All Replies (3)

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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


  • uses an invalid security certificate SSL_ERROR_BAD_CERT_DOMAIN
  • configured their website improperly

How to troubleshoot the error code "SEC_ERROR_UNKNOWN_ISSUER" on secure websites https://support.mozilla.org/en-US/kb/troubleshoot-SEC_ERROR_UNKNOWN_ISSUER

Modified by FredMcD

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Chosen Solution

Problem resolved but all info regarding Avast is wrong and should be updated. Still enough to figure out a fix, Thanks

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That was very good work. Well done.

tjlytle said

all info regarding Avast is wrong and should be updated

What information are you talking about?