Firefox Edge Browser Error Code SEC_ERROR_EXPIRED_CERTIFICATE: How to Fix It

Easy 5-20 minutes Medium Severity Verified June 2026
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Error Code
SEC_ERROR_EXPIRED_CERTIFICATE
Brand
Firefox Edge
Product Type
browser
Severity
Medium
DIY Difficulty
Easy
Estimated Fix Time
5-20 minutes
The SEC_ERROR_EXPIRED_CERTIFICATE error in Firefox means the security certificate for the website you are trying to visit has passed its expiration date, and Firefox is blocking the connection to protect you from potential security risks. This can happen because the website owner forgot to renew their SSL certificate, or because your computer's date and time settings are incorrect, tricking Firefox into thinking a valid certificate has expired. In most cases you can resolve this issue yourself in just a few minutes by checking your system clock, clearing browser data, or adjusting a few Firefox settings.
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How to Fix Error Code SEC_ERROR_EXPIRED_CERTIFICATE

  1. Check and Correct Your Computer's Date and Time

    If your computer's clock keeps resetting after you fix it, your CMOS battery on the motherboard may be dead. In that case, the battery will need to be replaced or you should consult a technician.

  2. Clear Firefox Browser Cache and Cookies

    Clearing cookies will log you out of most websites. Make sure you know your login credentials before proceeding.

  3. Check if the Website Certificate is Truly Expired

    Do not click 'Accept the Risk and Continue' on websites that handle sensitive data such as banking, shopping, or login pages. An expired certificate on these sites is a genuine security risk.

  4. Disable Security Software Interference Temporarily

    Only disable your antivirus temporarily and for testing purposes. Re-enable it immediately after your test to keep your computer protected.

  5. Update Firefox to the Latest Version

  6. Update Your Operating System

    Back up important files before running major operating system updates.

  7. Try the Website in a Different Browser

    Deleting cert9.db will remove any manually added certificate exceptions you have stored in Firefox. Locate your Firefox profile folder by typing 'about:profiles' in the Firefox address bar and clicking 'Open Directory' next to the root folder.
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When to Call a Professional

If you have tried all steps above and the error persists only on a specific website, the issue lies entirely with that website's server and you should contact the website owner or administrator to inform them their SSL certificate has expired and needs renewal. If your system clock keeps resetting repeatedly even after you correct it, a hardware technician should inspect and replace the CMOS battery on your computer's motherboard. If you are a website owner seeing this error on your own site, contact your web hosting provider or the certificate authority that issued your SSL certificate to arrange an immediate renewal.

Frequently Asked Questions

Is it safe to click 'Accept the Risk and Continue' when I see SEC_ERROR_EXPIRED_CERTIFICATE?
It depends on the website. For personal or non-sensitive websites you trust and visit regularly, the risk is relatively low. However, you should never bypass this warning on sites that require a login, handle payment information, or store any personal data, because an expired certificate means your connection could potentially be intercepted or you may be visiting a fraudulent copy of the site.
Why does SEC_ERROR_EXPIRED_CERTIFICATE only appear in Firefox and not Chrome?
Firefox manages its own certificate trust store separately from your operating system, while Chrome uses the operating system's certificate store. If only Firefox shows the error, it may be that Firefox's internal certificate database has become corrupted. Try deleting the cert9.db file from your Firefox profile folder (type about:profiles in the address bar to find it) and restarting Firefox so it can rebuild the file fresh.
Can a website's expired certificate hurt my computer or steal my data?
An expired certificate itself does not automatically harm your computer, but it means the encryption protecting your connection to the site can no longer be fully verified. This makes it easier for attackers on the same network to potentially intercept data you send to or receive from that site. Avoid entering passwords, credit card numbers, or personal information on any site showing this error.
How do I fix SEC_ERROR_EXPIRED_CERTIFICATE if it appears on every single website?
If you see this error on every site you visit, the most likely cause is that your computer's date or time is set incorrectly, which makes all certificates appear expired. Go to your system date and time settings, correct the date, time, and time zone, and enable automatic time synchronization. This should resolve the error across all websites immediately.
How long does it take for a website owner to fix an expired SSL certificate?
Once the website owner or administrator begins the renewal process, it can take anywhere from a few minutes to several hours for the new certificate to be issued and deployed, depending on the type of certificate and the hosting setup. Free certificates from services like Let's Encrypt can be renewed and applied in minutes, while premium certificates from other authorities can take longer to validate and install.

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