Mail in Alias Server

I have a strange problem with an Alias server and email.
I created an Alias server which is an alias of
The user mailboxes are created in the top level server. When I try to assing extra mailadresses (the to the users and save them, when I look into the user again the new mailadresses are gone. And when I sign in to with username.3dogshostel, I get the mailaddress of How can I best resolve this?

I just want the to be the main domain, and the should redirect everything to the .com.