One of the common issues, which users of the Firefox browser encounter while trying to browse, is the Secure Connection Failed warning. It is every bit as problematic as Firefox not responding, and can get on your nerves when you are seriously trying to connect to a particular website.
SSL (Secure Socket Layer) is an encrypted protocol that secures connections made on the internet. If a website has HTTPS:// at the beginning of the URL, then it has said to be secure. If Firefox find that a website is not secure, then you will get the Secure Connection Failed message, which is usually as bad as Firefox not responding, because you will not be able to connect to some websites. Following are some fixes you can try to remedy the situation.
If you have a proxy configuration, there is a chance of getting the Secure Connection Failed message. Remember, this is as bad as Firefox not responding.
The SSL of the website needs to be configured properly, or else the Secure Connection Failed message will appear.
If nothing works, try loading the website on another browser. If it loads without a problem on other browsers, it means that the issue stems from Firefox not finding the website to be trustworthy. In such cases, get in touch with browser support technicians for advanced help.