MX records, or Mail Exchange records, are specifically designed to point to a domain name and not directly to an IP address. The purpose is to identify the mail server that will accept email messages for that domain. The domain name in the MX record then resolves to an IP address using an A (Address) or AAAA (for IPv6) record.
Good to Know: In DNS, the zone records that accept IP addresses as valid entries are A records (for IPv4 addresses), AAAA records (for IPv6 addresses), and PTR records (used for reverse DNS lookups).
