Cam?n't send or receive mail. ( can't connect server)

I can’t send or receive mail. It says can’t connect server

Also I can’t issue ssl for hostname.
Previously everything was working fine. Suddenly this problem appeared.

Have you properly configured your DNS? If you can’t issue SSL to hostname your email will not work. Have you installed SSL previously and installed a new one?

Hi. Everything is fine. In cloudfare proxy is disabled. I tried to issue hostname ssl on new domain it failed. Also it fails in active domain which I already issued. Ssl for mail server and normal issue works fine. Previously issue host ssl was also working. Sufdenly this proboen appeared today
Also I figured a issue that accidently I deleted postfix from my server. Now it’s not getting installed.

What I could think of the solution is to start over. What OS are you using? There’s a step by step guide on YouTube in setting up email with Cyberpanel.