Recently, I have been blocked from visiting certain websites by Firefox, which are perfectly fine websites. I have to close out of Firefox and use Safari to connect to these websites. One of the websites is my City of San Bruno website: https://www.onlinebiller.com/sanbruno/index.html. This is just one of several websites in which I'm told the website there is a potential security issue. Did Not Connect: Potential Security Issue: I copy and pasted the warning below: "Firefox detected a potential security threat and did not continue to www.onlinebiller.com because this website requires a secure connection. What can you do about it? www.onlinebiller.com has a security policy called HTTP Strict Transport Security (HSTS), which means that Firefox can only connect to it securely. You can’t add an exception to visit this site. The issue is most likely with the website, and there is nothing you can do to resolve it. If you are on a corporate network or using anti-virus software, you can reach out to the support teams for assistance. You can also notify the website’s administrator about the problem." I contacted the City of San Bruno and was told it's a browser problem. As I mentioned above I can connect to these sites through Safari with no problem. Thank You for any explanation/assistance on how to connect to these websites using Firefox.