It means that when you load a website, Safari will check whether the website is using security encryption to protect your data.

if it cannot be verified, you may see Safari unable to establish a secure connection with the server flashing on the screen. This happened because Safari refused to upload the page.

on a Mac, anti-virus software may block Safari, so you will face the situation that Safari cannot establish a secure connection with the server. If you use antivirus software, add the site to the list of trusted sites to avoid future problems.

there is a situation

in general practice, all WHM configurations are set to be self-signed and all domain accounts configured in this SSL are set to * * * enjoy SSL. Solution: Anxin SSL certificate suggests using SSL-protected domain names to purchase special SSL certificates.

this dedicated SSL certificate will be issued by a trusted certificate authority (such as Symantec, GeoTrust, etc.) and include your domain name in SSL. Therefore, the Web browser will trust this SSL and no more warnings or messages will be displayed.