When your email service is created, we create a user named
"postmaster." This user is the Primary Domain Administrator. The
Primary Domain Administrator creates new email users, establishes
account quotas, receives system messages, etc.
It is important to check the Primary Domain Administrator's email
often, as the mail system will send quota notices to that account
(users approaching or over quota, domain approaching or over quota,
etc.). For this reason we strongly recommend adding a "postmaster" profile
to your email program to check the email box.