Pro Sites Subdomains

Hi. I am using Pro Sites on my multisite network. My website is trileq.com. I am a little confused on how this subdomain thing work when creating a new user and website on my network. When i create a new user and website from the admin panel called tutsi (tutsi.trileq.com), i get a default webpace (like it doesnt excist a website).

What am i doing wrong? What must i do to create a user and website that automaticly creates a subdomain aswell? Because, i can't get this to work :expressionless:

Thanks