If Firefox can't access a secure site (one that starts with https) you will see an error page with information about the error.

• To troubleshoot other error messages, see Websites don't load - troubleshoot and fix error messages.

Secure connection cannot be established

When a website you visit attempts to secure communication between your computer and the website, Firefox cross-checks this attempt to ensure that the certificate and the method the website is using are actually secure. If Firefox cannot establish a secure connection, you will see an error page with a description of the error, an option to report the error to Mozilla and a Try Again button.

Website issues

Some websites try using outdated (no longer secure) TLS mechanisms in an attempt to secure your connection. Firefox protects you by preventing navigation to such sites if there is a problem in securely establishing a connection. When this happens, you will see an error page.

If you experience this problem, contact the owners of the website and ask them to update their TLS version to a version that is still current and still secure.

Security software conflict

Security products that intercept secure connections by default can produce error pages on secure websites. Updating your security product or modifying your settings may resolve the issue. For more information, see this article's section on Antivirus products.

Alternatively, you can uninstall third-party security software and use Microsoft Security Essentials, the free antivirus offered by Microsoft for Windows 7.Alternatively, you can uninstall third-party security software and use Windows Defender, the built-in antivirus on Windows 8 and Windows 10.

AVAST and AVG security products

If you use a security product by Avast or AVG, it may be intercepting secure connections by default. Avast and AVG products may not be ready for the most recent and secure TLS 1.3 specification used in the latest versions of Firefox. As a result, Firefox users may see intermittent error pages on secure websites. To disable the interception of secure connections, see the article Managing HTTPS scanning in Web Shield in Avast Antivirus on the Avast support site.

ESET and NOD32 security products

If you use an ESET security product such as NOD32 Antivirus or ESET Internet Security, turning off one of the following settings and then turning it back on may help eliminate the error.

• Enable application protocol content filtering
• Enable SSL/TLS protocol filtering

For detailed instructions, see Disable SSL scanning in ESET Windows products at ESET Support and this AskVG.com article. If you have questions or concerns about modifying these settings, please visit ESET support.

Certificate warnings

Firefox uses certificates on secure websites to ensure that your information is being sent to the intended recipient and can't be read by eavesdroppers. For a list of certificate warnings and error codes, see the article What do the security warning codes mean?.

Incorrect date settings

If the date is not correct on your system, this can cause Firefox to detect that the website's security certificate is expired or invalid. You should ensure that your system clock is set to today's date and time (double-click the clock icon on the Windows taskbar). For information, see the article How to troubleshoot time related errors on secure websites.

If Firefox can't access a secure site (one that starts with https) you will see an error page with the heading Secure Connection Failed and a message about the error.

• If you see the error message Your connection is not secure, see the article What do the security warning codes mean?.
• To troubleshoot other error messages, see Websites don't load - troubleshoot and fix error messages.

Secure connection cannot be established

When a website you visit attempts to secure communication between your computer and the website, Firefox cross-checks this attempt to ensure that the certificate and the method the website is using are actually secure. If Firefox cannot establish a secure connection, you will see a Secure Connection Failed error page similar to the one shown below, with a description of the error, an option to report the error to Mozilla and a Try Again button:

The error page will also include the following information:

• The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.
• Please contact the website owners to inform them of this problem.

Website issues

Some websites try using outdated (no longer secure) TLS mechanisms in an attempt to secure your connection. Firefox protects you by preventing navigation to such sites if there is a problem in securely establishing a connection. When this happens, you will see the Secure Connection Failed error page.

If you experience this problem, contact the owners of the website and ask them to update their TLS version to a version that is still current and still secure.

Security software conflict

Security products that intercept secure connections by default can produce Secure Connection Failed and Your connection is not secure error pages on secure websites. Updating your security product or modifying your settings may resolve the issue. For more information, see this article's section on Antivirus products.

Alternatively, you can uninstall third-party security software and use Microsoft Security Essentials, the free antivirus offered by Microsoft for Windows 7.Alternatively, you can uninstall third-party security software and use Windows Defender, the built-in antivirus on Windows 8 and Windows 10.

AVAST and AVG security products

If you use a security product by Avast or AVG, it may be intercepting secure connections by default. Avast and AVG products may not be ready for the most recent and secure TLS 1.3 specification used in the latest versions of Firefox. As a result, Firefox users may see intermittent Secure Connection Failed error pages on secure websites. To disable the interception of secure connections, see the article Managing HTTPS scanning in Web Shield in Avast Antivirus on the Avast support site.

ESET and NOD32 security products

If you use an ESET security product such as NOD32 Antivirus or ESET Internet Security, turning off one of the following settings and then turning it back on may help eliminate the error.

• Enable application protocol content filtering
• Enable SSL/TLS protocol filtering

For detailed instructions, see Disable SSL scanning in ESET Windows products at ESET Support and this AskVG.com article. If you have questions or concerns about modifying these settings, please visit ESET support.

Certificate warnings

Firefox uses certificates on secure websites to ensure that your information is being sent to the intended recipient and can't be read by eavesdroppers. For a list of certificate warnings and error codes, see the article What do the security warning codes mean?.

Incorrect date settings

If the date is not correct on your system, this can cause Firefox to detect that the website's security certificate is expired or invalid. You should ensure that your system clock is set to today's date and time (double-click the clock icon on the Windows taskbar). For information, see the article How to troubleshoot time related errors on secure websites.