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

Avatar for Username

Rechercher dans l’assistance

Évitez les escroqueries à l’assistance. Nous ne vous demanderons jamais d’appeler ou d’envoyer un SMS à un numéro de téléphone ou de partager des informations personnelles. Veuillez signaler toute activité suspecte en utilisant l’option « Signaler un abus ».

En savoir plus
Ce sujet de discussion a été archivé. Veuillez poser une nouvelle question si vous avez besoin d’aide.
Résolu Archivé

firefox is useless - says EVERY site has bad certificate - even MOZILLA will not load

Firefox Autre
FredMcD a répondu
handyman321
handyman321

The owner of mozilla.com has configured their website improperly. To protect your information from being stolen, Firefox has not connected to this website.

The owner of www.google.com has configured their website improperly. To protect your information from being stolen, Firefox has not connected to this website.

The owner of www.msn.com has configured their website improperly. To protect your information from being stolen, Firefox has not connected to this website.

The owner of mozilla.com has configured their website improperly. To protect your information from being stolen, Firefox has not connected to this website. The owner of www.google.com has configured their website improperly. To protect your information from being stolen, Firefox has not connected to this website. The owner of www.msn.com has configured their website improperly. To protect your information from being stolen, Firefox has not connected to this website.

Toutes les réponses (2)

Shadow110
Shadow110

Hi, sounds like some corruption in a file. Please : uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files , C:\Program Files(x86) & C:\ProgramData Then restart system. Then run Windows Disk Cleanup. (Note: This should be Pinned and run Weekly, If never done below expect 10's of gig's) Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. But you should make a back up before you do :

Reinstall with Current Release Firefox 59.0.2 with a Full Version Installer

Please let us know if this solved your issue or if need further assistance.

FredMcD
FredMcD

Solution choisie

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