Originally Posted by WDL
... The domain is included as a virtualhost in apache2.conf ...
Maybe the Apache setup on Ubuntu is different to Centos, but AFAIK the virtual host for your site should not be in apache2.conf.
1/ Do you mean apache2.conf or httpd.conf?
2/ The virtual host settings should be in a file (one per domain) in "sites-available" with a pointer from "sites-enabled".