From MozillaZine Knowledge Base

SSL (Secure Sockets Layer) is a security protocol that secures communication over the Internet. Most banking sites and online stores require sensitive information be sent over SSL. This article deals with causes of a "SSL is disabled" error message. For information on other messages received when accessing secure sites, see Error loading secure sites.

Check SSL settings

Check that SSL is enabled.

• Firefox 2: "Tools -> Options -> Advanced -> Encryption"
• Firefox 1.5: "Tools -> Options -> Advanced -> Security"
• Mozilla Suite: "Edit -> Preferences -> Privacy & Security -> SSL"

"Use SSL 3.0" and "Use TLS 1.0" should both be checked.

Check proxy settings

If you're using a manual proxy, make sure "Use this proxy for all protocols" and "SSL proxy" in "Tools -> Options -> Advanced -> Network / Connection -> Settings" (Firefox 2) or "Tools -> Options -> General -> Connection Settings" (Firefox 1.5 or earlier) are set to the correct values.

Check firewall

Mozilla applications require a loopback connection to be available for SSL. Check your firewall settings to make sure you have not blocked incoming connections to Mozilla applications. See this article for details on firewall configuration.

Clear cache

You may simply have an out of date version of the page in your cache. Clear the cache.

• Firefox 2: "Tools -> Options -> Advanced -> Network / Cache -> Clear Now"
• Firefox 1.5: "Tools -> Options -> Privacy -> Cache -> Clear"
• Mozilla Suite: "Edit -> Preferences -> Advanced -> Cache -> Clear Cache"

SSL diagnostics

You can try this SSL test. If your browser passes, it's likely a problem with the site you're trying to connect to.

SSL disabled on Windows 9x systems after upgrade

If you're on Windows 98 or ME and SSL no longer works after updating to Firefox 2.0.0.2 or later, Firefox 1.5.0.10 or later 1.5 builds, and Thunderbird 1.5.0.10 and later 1.5 builds, you may be able to fix it by installing IE 6.0 SP1.[1][2]

SSL support

If, rather that downloading the program from Mozilla, you compiled the Mozilla application yourself or received it from an administrator, it's possible SSL support was disabled.

Other solutions

Try the standard diagnostic.

See also

• Cannot connect securely because the site uses an older insecure version of the SSL protocol
• Could not initialize the browser security component
• OCSP error when accessing secure sites