out.mail.icann.org has no MX records.
Question and response
Question
dig out.mail.icann.org. MX
Answer
The response has no answer records.
Authority
icann.org. 3600 SOA sns.dns.icann.org. noc.dns.icann.org. 2026022407 10800 3600 1209600 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0