An MX record defines how email is received by the domain owners.
An MX record tells the world how to send email to addresses at your domain name. Without an MX record, a website cannot receive email.
Even if a website does not intend to receive email, they should still set an MX record. This is because many big email receiving servers will flat out reject incoming messages if the sending domain does not have an MX record. This is done for spam prevention purposes.
Ready to validate your website for this test and 100+ others?