TheCrimsonHorror

Had a user today that added a new domain to his reseller account. 

Apparently he had this domain with us before, and transferred it over to GoDaddy for hosting, then was bringing it back. 

I've seen this happen a few times when the IP address they were pointing to was incorrect, or the httpd.conf was pointing to the home folder or IP incorrectly. 

I tried the basics like rebuilding the httpdconf and still getting issues. 

Had a look at the Zone file for the domain, and saw that on our side, the authoratative nameserver were set to his previous host. 
Rebuilt the Zone file, and it appears that the site started working. 

Probably something I should have thought of earlier, but at least I got to the bottom of it.