Websites Not loading

I have installed cyberpanel in my droplet in digitaloccean.
After that I have added few websites to it. Everything was working fine till yesterday and suddenly the websites added in cyberpanel stopped working.

I dont know the issue.

Restart your server and see.

Your server or DNS server or web-server is not running.

I have done that many times.
But no use.

I have other websites loading without any errors in the same server:

You can send login details privately. I will have a check and guide you solution.

PM sent.
But its horrible.
So I shifted two of my websites to new droplet.

Same happening with my website the main domain is opening but subdomain is not opening nor showing any errors

Your sites are up only looks like you have self signed SSL certificate. If you use cloudflare disable proxy and try issue SSL again.