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?.
• For troubleshooting 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Some websites try using outdated (no longer secure) TLS mechanisms in an attempt to secure your connection.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

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 with the error code SSL_ERROR_RX_RECORD_TOO_LONG on secure websites such as Google and others. As a workaround, you can disable the interception of secure connections in your AVAST or AVG settings:

1. Open the dashboard of your Avast or AVG application.
2. Go to Menu > Settings > Components and click Customize next to Web Shield.
3. Uncheck the box next to Enable HTTPS Scanning and confirm this by clicking OK.

For more information, see 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 this AskVG.com article. If you have questions or concerns about modifying these settings, please visit ESET support.

Other security products

Other security products that intercept secure connections by default can produce Secure Connection Failed and Your connection is not secure error pages on secure websites. For more information, see this article's section on Antivirus products.

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.