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 {for not fx66}the error message ''Your connection is not secure''{/for}{for fx66}another security error message{/for}, 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]]. __TOC__ = 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 {button Try Again} button: [[Image:fx60SecureConnectionFailed-ErrorCode]] 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 = Website issues = Some websites try using outdated (no longer secure) [http://wikipedia.org/wiki/Transport_Layer_Security ''TLS''] mechanisms in an attempt to secure your connection.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.<!-- See https://support.mozilla.org/en-US/kb/what-does-your-connection-is-not-secure-mean/discuss/6480#post-13160 --> 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'' errors or security warnings on secure websites. Updating your security product or modifying your settings may resolve the issue. For more information, see [[How to troubleshoot security error codes on secure websites#w_antivirus-products|this article's section on Antivirus products]]. {for win7}Alternatively, you can uninstall third-party security software and use [https://support.microsoft.com/help/14210/security-essentials-download Microsoft Security Essentials], the free antivirus offered by Microsoft for Windows 7.{/for}{for win8,win10}Alternatively, you can uninstall third-party security software and use Windows Defender, the [https://www.microsoft.com/windows/comprehensive-security built-in] antivirus on Windows 8 and Windows 10.{/for} == AVAST and AVG security products == If you use a security product by [https://www.avast.com Avast] or [https://www.avg.com AVG], it may be intercepting secure connections by default. Avast and AVG products may not be ready for the most recent and secure [http://wikipedia.org/wiki/Transport_Layer_Security 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.<!-- https://bugzilla.mozilla.org/show_bug.cgi?id=1468892 --> To disable the interception of secure connections, see the article [https://support.avast.com/en-us/article/189/ Managing HTTPS scanning in Web Shield in Avast Antivirus] on the Avast support site. <!-- commented out based on https://bugzilla.mozilla.org/show_bug.cgi?id=1468892#c50 --> <!-- Another workaround is to set Firefox not to try TLS 1.3: # [[T:aboutconfig]] # In the search box above the list, type or paste '''TLS''' and pause while the list is filtered # Double-click the {pref security.tls.version.max} preference to display a dialog where you can modify the value from '''4''' to '''3''' (or, in other words, from TLS 1.3 to TLS 1.2) and then click OK.--> == ESET and NOD32 security products == If you use an [https://www.eset.com 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 [https://support.eset.com/kb3126 Disable SSL scanning in ESET Windows products] at ESET Support and [http://www.askvg.com/fix-secure-connection-failed-problem-in-mozilla-firefox-web-browser/ this AskVG.com article]. If you have questions or concerns about modifying these settings, please visit [http://support.eset.com/ ESET support].<!-- See https://support.mozilla.org/questions/1174146 and https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message/discuss/7169 --> = Certificate errors = 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. If you have tried the suggestions given in the preceeding sections but you continue to see the ''Secure Connection Failed'' error, see these articles for help with specific certificate errors: *[[Certificate Pinning Reports]]<br>Error code: MOZILLA_PKIX_ERROR_KEY_PINNING_FAILURE *[[Certificate contains the same serial number as another certificate]]<br>Error code: SEC_ERROR_REUSED_ISSUER_AND_SERIAL == Other certificate issues == 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. See [[How to troubleshoot time related errors on secure websites]]. See [[What do the security warning codes mean?]] for information about other certificate warnings and error codes.

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 secureanother security error message, 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. 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 errors or security warnings 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 errors

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. If you have tried the suggestions given in the preceeding sections but you continue to see the Secure Connection Failed error, see these articles for help with specific certificate errors:

• Certificate Pinning Reports
  Error code: MOZILLA_PKIX_ERROR_KEY_PINNING_FAILURE

• Certificate contains the same serial number as another certificate
  Error code: SEC_ERROR_REUSED_ISSUER_AND_SERIAL

Other certificate issues

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. See Troubleshoot time-related errors on secure websites.

See What do the security warning codes mean? for information about other certificate warnings and error codes.