I ran into an issue on Hostgator today whereby I could not get my sub-domains working in a fresh WordPress multi-site installation.
mydomain.com was working fine, but subsite.mydomain.com was displaying the default Hostgator page.
The issue was that my wildcard sub-domain was pointing to the “/public_html” document root. When I changed that to “/public_html/mydomain.com” everything worked fine.
I hope this post saves someone in this world from a headache! 🙂