ip2.directadmin.dev has no MX records.
Question and response
Question
dig ip2.directadmin.dev. MX
Answer
The response has no answer records.
Authority
directadmin.dev. 1800 SOA macy.ns.cloudflare.com. dns.cloudflare.com. 2396677929 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0