humsmtp.boardbooks.com has no MX records.
Question and response
Question
dig humsmtp.boardbooks.com. MX
Answer
The response has no answer records.
Authority
boardbooks.com. 1800 SOA ns1-03.azure-dns.com. itservices.boardbooks.com. 2020092200 3600 600 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0