smtp-relay.midcentury.com has no MX records.
Question and response
Question
dig smtp-relay.midcentury.com. MX
Answer
The response has no answer records.
Authority
midcentury.com. 3600 SOA ns.adams.net. noc.adamstel.com. 2026010901 7200 1800 1209600 43200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0