How to map a domain thats been mapped before?

I deleted my network to do a huge rework but I did not "unmap" domain names. I just deleted everything, Well now I am trying to remap a domain name to a new subsite within the network. It has the same Ip adress and all that so I did not have to change a thing. Only the subdomain name has changed. Now this time the domain is not mapping. Is there something else I must delete to re map the domain? I got a new database as well. I wiped everything from the old install.