I have centos 7 want only the server as the only domain...

Can I set up cwp on a centos 7 server without using a domain? They host is server.site.com and the system is site.com.
When I try to set up cwp I get errors that server.sit.com and site.com and are not same. Without setting up domain site.com how to I get to use the email?
Thanks

CentOS 7 is EOL.
So you would want to setup a server using AlmaLinux 8.

CWP has to have a Hostname, which is usually a sub-domain.

So if you TLD is domain.com, make a DNS A record for srv1.domain.com, and then you can create a user account for domain.com
This user account sets up the web, email, DNS etc. as CWP is a complete hosting solution.

If you just want to use email, you can. But the other items will still be there unused, since you wouldn't be pointing any A records to those services.

CWP doesn't use base hostname except for panel access.

Thanks. I I will look in to it. Tried using iRedMail but it works only  on centos 8 stream and centos 9 stream. Both are to big for my server.

iRedMail works on AlmaLinux 8 and 9.
Even works on FreeBSD.

Just uses Postfix & Dovecot like CWP does. Also includes SOGo

What are your server specs?

8 & 9 aren't any more resource hogs than 7 was.