I have created a subdomain with its folder placed and /public_html like so:
If I go to /websites/site.com/sub.site.com on CyberPanel, and click on Preview, it will correctly show the index.html content under /public_html/sub.site.com.
But if I attempt to access it directly at sub.site.com it will show:
We can’t connect to the server at sub.site.com.
I can access the main domain just fine.