Hi, are you having problems connecting to a site, or is this after the page loads, the lock icon in the address bar has a slash through it?

Connection errors have a variety of error codes. If you could share the code you're seeing, that would help. It usually has some capital letters and underscores -- SEC_ERROR_SOMETHING. Sometimes you need to click an Advanced button to find the code. This article has more information on the most common codes: How to troubleshoot security error codes on secure websites.

Do you get an error page or merely a padlock that show that the connection is insecure on hover ? The latter could be caused by content loaded over an insecure http:// connection.

• https://support.mozilla.org/en-US/kb/mixed-content-blocking-firefox
• https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop