Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Firefox doesn't load any website from now on and tells me "this connection is not secure". What can I do? I need to have access to my tabs in firefox again. Thx

  • 3 replies
  • 1 has this problem
  • 1 view
  • Paskiausią atsakymą parašė FredMcD

more options

Dear ladies and gentlemen, unfortunately my firefoy today told me that a security program (this note was coming from my kaspersky security system, but it said that there is another system which wants to secure my browser) wants to secure my browser and I said "accept". Afterwards I coulnd`t load any websites anymore cause Firefox always tells me "this connection is not secure". I can not add exceptions. Afterwards I deactivated the security System in the add-ons again but I still have the problem that I can't load any page with firefox. I can't find any security setting to help me. Firefox tells me:"Fehlercode: SEC_ERROR_UNKNOWN_ISSUER" I also can't leave this website and send the error to Mozilla (as you can see on the added picture). Can you please help me and tell me what I can do to be able to use Firefox and all my safed tabs again? Thank you very much! Yours sincerely, Melanie Westermann

Dear ladies and gentlemen, unfortunately my firefoy today told me that a security program (this note was coming from my kaspersky security system, but it said that there is another system which wants to secure my browser) wants to secure my browser and I said "accept". Afterwards I coulnd`t load any websites anymore cause Firefox always tells me "this connection is not secure". I can not add exceptions. Afterwards I deactivated the security System in the add-ons again but I still have the problem that I can't load any page with firefox. I can't find any security setting to help me. Firefox tells me:"Fehlercode: SEC_ERROR_UNKNOWN_ISSUER" I also can't leave this website and send the error to Mozilla (as you can see on the added picture). Can you please help me and tell me what I can do to be able to use Firefox and all my safed tabs again? Thank you very much! Yours sincerely, Melanie Westermann

Chosen solution

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

Skaityti atsakymą kartu su kontekstu 👍 1

All Replies (3)

more options

Chosen Solution

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

more options

Thank you very much, this worked! :)

more options

Glad to help. Safe Surfing.