I have used few days, now i have a problems:

Exam: My email: admin@datminh.com.vn or any mail in my domain can send and received orther email 

But in my domain they cann't receive email: adminh@datminh.com.vn send mail to user@datminh.com.vn, and user@datminh.com.vn dont see any email?

Thx & Regards