If you get message "Software is Preventing Firefox From Safely Connecting to This Site. Most likely a safe site, but a secure connection could not be established. This issue is caused by The original certificate provided by the web server is untrusted., which is either software on your computer or your network." lets see the tutorial. 1. With Burp suite running, visit http://burp in your browser and click the "CA Certificate" link to download and save your Burp CA certificate. Remember where you save the Burp CA certificate.