Windows 10 reached EOS (end of support) on October 14, 2025. If you are on Windows 10, see this article.

Tìm kiếm hỗ trợ

Tránh các lừa đảo về hỗ trợ. Chúng tôi sẽ không bao giờ yêu cầu bạn gọi hoặc nhắn tin đến số điện thoại hoặc chia sẻ thông tin cá nhân. Vui lòng báo cáo hoạt động đáng ngờ bằng cách sử dụng tùy chọn "Báo cáo lạm dụng".

Tìm hiểu thêm
Chủ đề này đã đóng và được lưu lại. Vui lòng hỏi một câu hỏi mới nếu bạn cần giúp đỡ.
Đã khóa Đã lưu trữ

SEC_ERROR_UNKNOWN_ISSUER error

SuMo Bot đã trả lời
SuMo Bot

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

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

Tất cả các câu trả lời (3)

  • 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

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
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

This question has been locked because the original author has deleted their account. While you can no longer post new replies, the existing content remains available for reference.