Firefox Edge Browser Error Code MOZILLA_PKIX_ERROR_SELF_SIGNED_CERT: How to Fix It

Easy 5-20 minutes Medium Severity Verified June 2026
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Error Code
MOZILLA_PKIX_ERROR_SELF_SIGNED_CERT
Brand
Firefox Edge
Product Type
browser
Severity
Medium
DIY Difficulty
Easy
Estimated Fix Time
5-20 minutes
The Firefox error MOZILLA_PKIX_ERROR_SELF_SIGNED_CERT appears when a website presents a security certificate that was not issued by a trusted Certificate Authority (CA) — meaning the site essentially vouched for itself. This is common on internal corporate networks, home routers, development servers, and older equipment. While the error is not always dangerous, Firefox blocks the page by default to protect you from potential man-in-the-middle attacks or unverified sites.
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Tools You'll Need

How to Fix Error Code MOZILLA_PKIX_ERROR_SELF_SIGNED_CERT

  1. Understand the Risk Before Proceeding

    Never bypass this warning on public-facing websites or when entering passwords, credit card numbers, or personal data. Only proceed if you fully trust and own the destination.

  2. Use the Advanced Override to Proceed (Temporary Bypass)

    This exception is stored per Firefox profile. Other browsers or users on the same machine will still see the warning.

  3. Check and Correct Your System Clock

  4. Clear Firefox's Certificate Cache and Cookies

  5. Disable Antivirus or Firewall HTTPS Scanning Temporarily

    Disabling HTTPS scanning reduces your antivirus protection temporarily. Only do this for testing purposes, and re-enable it afterward.

  6. Manually Import the Self-Signed Certificate into Firefox

    Only import certificates from devices you personally own or that are officially distributed by your IT department. Never import a certificate from an unknown source.

  7. Test in a Fresh Firefox Profile

    Refreshing Firefox will remove extensions, customizations, and some stored data. Back up bookmarks before proceeding.

  8. If You Own the Server — Replace the Self-Signed Certificate

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When to Call a Professional

Contact your IT department or a network administrator if this error appears on a corporate intranet or work-issued device — they will need to push the correct certificate through your organization's managed device policy. If you own a website that is showing this error to users, contact your web hosting provider or a qualified web developer to install a properly issued SSL/TLS certificate. If you are unsure whether a site is trustworthy and you cannot verify it yourself, do not proceed and consult a cybersecurity professional.

Frequently Asked Questions

Is it safe to click 'Accept the Risk and Continue' on the MOZILLA_PKIX_ERROR_SELF_SIGNED_CERT error?
It depends entirely on the site. If the destination is your own home router, a local development server, or an internal network device you trust and control, it is generally safe to proceed. However, if this warning appears on a public website, a login page, or a site you reached via a link in an email, do not bypass it — it could indicate a fraudulent or compromised site.
Why does Firefox show this error but Chrome or Edge does not?
Firefox uses its own built-in certificate store rather than the operating system's certificate store. Chrome and Edge use the Windows or macOS system trust store, so if a certificate was imported at the OS level it will be trusted in those browsers automatically. Firefox requires you to import the certificate separately through its own certificate manager, or configure it to use the OS trust store via the 'security.enterprise_roots.enabled' setting in about:config.
How do I make Firefox trust the OS certificate store to avoid this error on internal sites?
Type 'about:config' in the Firefox address bar and press Enter. Accept the risk warning, then search for 'security.enterprise_roots.enabled' and set its value to 'true' by double-clicking it. Firefox will now read trusted certificates from your operating system's root certificate store. This is especially useful in corporate environments where certificates are pushed via Group Policy.
How do I permanently fix this error on my router's admin page?
The most reliable fix is to download your router's self-signed certificate and import it into Firefox's certificate manager as a trusted authority (see Step 6 above). Alternatively, many modern routers allow you to install a custom SSL certificate — check your router's administration documentation. Some routers also support accessing the admin panel over plain HTTP (not HTTPS) which avoids the certificate check entirely, though this is less secure on shared networks.
Will this error affect all users or just me?
This error will appear for any user whose browser does not trust the self-signed certificate used by the server. It is not specific to your account or computer — it is a property of the certificate on the server. The permanent fix is to replace the self-signed certificate with one from a trusted Certificate Authority (like Let's Encrypt), which will resolve the error for every visitor using any browser.

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