How to fix “This Connection is Untrusted” in Firefox?

Mozilla Firefox displays “This Connection is Untrusted” warning message when there is a problem with a secure URL (URL with https). The problem is usually associated with security certificates. Learn how to resolve or bypass this error message. You may notice “This Connection is Untrusted” when you try to open a secure URL that uses an expired or wrongly configured security certificate. It may also appear due to a wrongly configured system.

Why this warning message? Before starting an encrypted communication, a secure website presents it’s security certificate. If there is a problem with the security certificate, the web browser will fail to verify the identity of that website. In such a situation, Mozilla Firefox throws in the error or warning message on your browser window. This is done to ensure your privacy and protect you from possible identity theft.

The “This Connection is Untrusted” warning can be fixed or bypassed by easily. But you should be more careful. Browsing a https URL without valid security certificate posses security threat. If you want to perform a financial transaction (banking, shopping etc) or share sensitive information, you should avoid such URLs. But if you are casually browsing and the site in question is a trusted one, you may try the following.

How to bypass “This Connection is Untrusted”?

1. First try to load the URL without https (type http:// not https://). This often works, specially when the https is added by mistake. If that doesn’t work, go back to https.
2. Firefox will display the error message. Press ‘I Understand the Risks‘. You’ll notice the Add Exception button. Press it.



3. The Add Security Exception dialogue box will appear. Uncheck Permanently store this exception and press Confirm Security Exception button. The webpage will reload.

Resolving ‘This Connection is Untrusted”

Bypassing is not a solution to a problem. Also, sometimes the root cause of a problem lies in your own system. In such a case, you’ll notice the warning message on every secure website. So, try to fix this problem by digging a little deeper. When “this connection is Untrusted” message appears, press the ‘Technical Details‘ button. Firefox will provide you some more details on the problem. It will show you a error message and also an error code. Example: invalid security certificate with an error code: ssl_error_bad_cert_domain. Note that message and error code. If the error message matches with any of the following, try to fix it by applying the solution.

Error message: The certificate is only valid for (site name)
Error code: SSL_ERROR_BAD_CERT_DOMAIN

Solution: This error means that the security certificate was meant for another site(s). Check the domain names mentioned in the error details. If this is a case of presence or absence of www, you may try adding or removing www to the URL in question. Or, simply try loading the page without https.

Error message: certificate will not be valid until

Error code: SEC_ERROR_EXPIRED_ISSUER_CERTIFICATE

Solution: The certificate will not be valid until (date) error is associated with wrongly set date and time. Check your system and set the clock to today’s date and time. You can do that by clicking on the clock on your taskbar.

Error Message: The certificate expired on date

Error code: SEC_ERROR_EXPIRED_CERTIFICATE

Solution: The certificate expired on date error appears when a website’s security certificate has expired. But sometimes, it appears on a system with wrongly set date and time. Check the date on your system. If it is incorrect, set the clock to today’s date and time.

Error Message: The certificate is not trusted because the issuer certificate is unknown

Error code: SEC_ERROR_UNKNOWN_ISSUER

Solution: This error message appears when server fails to send proper intermediate certificates. But it may also appear due to SSL scanning by security software like Bitdefender, Avast, or Kaspersky. Check your system and ensure that SSL scanning is turned off on your antivirus.

Error message: The certificate is not trusted because it is self-signed

Error code: SEC_ERROR_UNTRUSTED_ISSUER

Solution: Self-signed certificates are common in intranet websites. If you are browsing an intranet site, you can safely bypass the warning by following the steps mentioned above. Never ever open a public site (non-intranet site) with self-signed certificate.