how we can setting an email that have the same name of the domain, for example domain@domain.com.
When we save the new email Virtualmin block this.
best regards to all
antonio

That email address already exists. It's the default email address of the virtual server account. It also happens to be the administrative user account of the virtual server...so if you want to give this email address to a non-trusted user, you might want to make it forward to a less privileged account (or use the advanced section of the Create Virtual Server form a different user name so this one is free).