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SEC_ERROR_UNKNOWN_ISSUER error

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Hi For some reasons im unable to access these websites zoopla.co.uk, rightmove.couk, mouseprice.com, primelocation.com, ebay.co.uk on my firefox 78.4.0esr and get the error SEC_ERROR_UNKNOWN_ISSUER with no option to advance. I can access these sites on Internet explorer & chrome but weird why Firefox is blocking it. Is there a workaround this please


Ps: i have no 3rd party anti virus and tried using this article https://support.mozilla.org/en-US/kb/error-codes-secure-websites but no joy

Thanks

All Replies (3)

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  • MOZILLA_PKIX_ERROR_MITM_DETECTED
  • 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


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

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

Websites don't load - troubleshoot and fix error messages

http://kb.mozillazine.org/Error_loading_websites

What do the security warning codes mean

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Can you retrieve the certificate and check the issuer ?

You can check details about the issuer of the certificate and the certificate chain.

  • click the "Advanced" button on the error page to show more detail
  • click the blue "View Certificate" link to inspect the certificate chain in the Certificate Viewer
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Hi @Cor-el, Forcepoint Cloud Web Enforce is the issuer

cor-el said

Can you retrieve the certificate and check the issuer ? You can check details about the issuer of the certificate and the certificate chain.
  • click the "Advanced" button on the error page to show more detail
  • click the blue "View Certificate" link to inspect the certificate chain in the Certificate Viewer