sea-shared-16.hostwindsdns.com has no MX records.
Question and response
Question
dig sea-shared-16.hostwindsdns.com. MX
Answer
The response has no answer records.
Authority
hostwindsdns.com. 3600 SOA dns1.hostwindsdns.com. abuse.hostwinds.com. 2017051200 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0