Mail for additional domains.
WHAT IS POSSIBLE
Each addon domain can have its own email accounts.
Alias domains can receive mail, routed to your main domain's accounts.
CREATING ACCOUNTS
cPanel, Email Accounts. Select the domain from the list.
WHAT TO CHECK
MX records for that domain point here SPF and DKIM are configured for it
Check cPanel Email Deliverability, which reports per domain.
THE COMMON PROBLEM
An addon domain added, email accounts created, and mail does not arrive.
Usually the MX records or the routing setting.
FOR ALIAS DOMAINS
Mail to the alias can be delivered to the main domain's accounts.
Useful for a rebrand, so mail to the old address still arrives.
IF YOU DO NOT WANT MAIL ON A DOMAIN
Remove its MX records. A domain with none receives no mail.
Consider publishing an SPF record permitting nothing, so nobody can forge mail from it.
FOR DEFENSIVE REGISTRATIONS
That last point is worth doing.
