How To Set Up Apache with a Free Signed SSL Certificate on a VPS https
On a vanilla Apache2 install in CentOS, when you install mod_ssl it will automatically add a configuration file in:
This configuration file contains a default virtual host definition for port 443, named default:443. If you also have your own virtual host definition for 443 (i.e. in httpd.conf) then you will have a confict. Since the conf.d files are included first, they will win over yours.
To solve the conflict you can either remove the virtual host definition from conf.d/ssl.conf or update it to your own settings.