Secure connection failed and Firefox did not connect

+ This article explains why you may see a + Secure Connection Failed or a + Did Not Connect: Potential Security Issue error page and what + you can do. +

+ 1 + Secure connection cannot be established +
- + 1.1 + Secure Connection Failed +
- + + 1.2 + Did Not Connect: Potential Security Issue +
+
+ 2 + Website issues +
- + 2.1 + TLS version unsupported +
- + 2.2 + HSTS required +
+
+ 3 + Security software conflict +
+ 4 + Incorrect system clock +
+ 5 + Other secure connection issues +

+ Secure connection cannot be established +

+ When a website that requires a secure (https) + connection tries to secure communication with your computer, Firefox + cross-checks this attempt to make sure that the website certificate and + the connection method are actually secure. If Firefox cannot establish a + secure connection, it will display an error page. +

Secure Connection Failed

+ A Secure Connection Failed error page will include a + description of the error, an option to report the error to Mozilla and a + Try Again button. There is no option to add + a security exception to bypass this type of error. +

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. +

+ Did Not Connect: Potential Security Issue +

+ Certain secure connection failures will result in a + Did Not Connect: Potential Security Issue error page. +

+ The error page will include a description of the potential security + threat, an option to report the error to Mozilla and an + Advanced… button to view the error code and + other technical details. There is no option to add a security exception + to visit the website. +

Website issues

TLS version unsupported

+ Some websites try using outdated (no longer secure) Transport Layer + Security(TLS) mechanisms in an attempt to secure your + connection.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. Contact the + owners of the website and ask them to update their TLS version to a + version that is still current and still secure. +

+ Starting in Firefox version 74, the minimum TLS version allowed by + default is TLS 1.2. Websites that don't support TLS version 1.2 or + higher will display a Secure Connection Failed error page with + Error code: SSL_ERROR_UNSUPPORTED_VERSION and a message that + This website might not support the TLS 1.2 protocol, which is the + minimum version supported by Firefox. + The error page may also include a button, + Enable TLS 1.0 and 1.1 that will allow you + to override the minimum TLS requirement; however, Mozilla plans to + remove this option and permanently disable TLS 1.0 and 1.1 in a future + version of Firefox. +

HSTS required

+ Other websites may require HTTP Strict Transport Security (HSTS) and + will not allow access with an insecure connection. +

Security software conflict

+ Many security products use a feature that intercepts secure connections + by default. This can produce connection errors or warnings on secure + websites. If you see secure connection errors on multiple secure + websites, updating your security product or modifying its settings may + resolve the issue. +

+ + Alternatively, you can uninstall third-party security software and use + Windows Defender, the built-in antivirus on Windows 8 and Windows 10. + +

Incorrect system clock

+ 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. An incorrect system date can cause Firefox to detect that + the website's security certificate is expired or invalid. Make sure your + computer is set to the correct date, time and time zone. +