Thanks for the answer.
I believe that you are talking about HC9 because I don't have any cluster menu in HC8, but I tried to follow your directions anyway.
The IP address is configured and bind, indeed I'm using the portal for configuring and testing directly from my desktop and connecting with a browser. The server has only one IP, hence I would like to use name based web sites.
In "System / My Server / Nat manager" the public ip address is configured with netmask 255.255.255.255
In "My server / IP address manager" the reseller is associated to the internal IP of the server
In "My server / Name/IP Based settings" the reseller is associated to "IP Based domains", because the option "Name based only" is grey. It was not grey before making the previous step, alas associating the server IP to the reseller.
What is strange is that when I log in as the reseller and create a web server, the only web server type that I'm allowed t choose is "Name based domain" and the error I receive is still the same: "No Name Based Domain IP address found."
Why does this happen? What I'm missing?