'Safari Can't Establish a Secure Connection to Server' Issue
If you spend a lot of time on the Internet, then you may have noticed a minor issue that affects users of Safari and other Web browsers. The 'Safari Can't Establish a Secure Connection to Server' Issue is not that common, but you may end up experiencing it even if you are trying to browse a website that used to work just fine a few hours ago. Typically, this issue occurs because there is a problem with your browser's configuration, your network settings, or with the security certificate that the website uses. Below, we will teach you some of the best ways to troubleshoot the 'Safari Can't Establish a Secure Connection to Server' Issue.
Use Alternative DNS Settings
The Domain Name System (DNS) is responsible for, simply put, resolving domain names to IP addresses. While your Internet Service Provider (ISP) has probably assigned a custom DNS server for you, it might be good to replace it with the Google DNS servers if you are experiencing any browser issues. You can do this by going to System Preferences -> Network -> DNS. After this, use the '+' button to add the DNS addresses 18.104.22.168 and 22.214.171.124.
Use an Alternative Web Browser
Some versions of Safari tend to be very strict about the security certificates and encryption standards that websites use. The high strictness levels may sometimes result in the 'Safari Can't Establish a Secure Connection to Server' Issue. If you are certain you are visiting a legitimate page, then you can use an alternative Web browser to bypass the restriction.
Check your Antivirus Software
Another reason why you may be encountering the 'Safari Can't Establish a Secure Connection to Server' Issue is because your antivirus software suite is being too strict when it comes to securing your browsing sessions. If the issue occurs when you visit a website that you know is legitimate, then turning off your antivirus software temporarily or fixing up its settings may help resolve the problem.