The first step in working with Email module is to set up a Domain name that can be used for email. Once a domain has been set up for email it can then have Mailboxes, Forwarders and Aliases associated with it.
You can only create an Email Domain if that Domain is already managed by the SiteHost Control Panel (see the Domains section for more details).
You can only delete an Email Domain if there are no existing Mailboxes, Aliases or Forwarders associated with it.