Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

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

error code: Mozilla_PKIX_Error_not_yet_valid_issuer_certificate?

  • 1 cavab
  • 1 has this problem
  • 1 view
  • Last reply by philipp

more options

when trying to open certain websites, I receive the error code above.

when I click on "Advanced"

Foxfire using HTTP Strict Transport Security may not connect to this site securely so it is not possible to add an exception for this certificate.

How do I override or delete this error code to open the desired website

when trying to open certain websites, I receive the error code above. when I click on "Advanced" Foxfire using HTTP Strict Transport Security may not connect to this site securely so it is not possible to add an exception for this certificate. How do I override or delete this error code to open the desired website

All Replies (1)

more options

hi, please check that your system is set to right date, time & timezone! How to troubleshoot time related errors on secure websites