mail7.sanmargroup.com has no MX records.
Question and response
Question
dig mail7.sanmargroup.com. MX
Answer
The response has no answer records.
Authority
sanmargroup.com. 600 SOA ns49.domaincontrol.com. dns.jomax.net. 2025120901 28800 7200 604800 600
Additional
. 0 OPT ; payload 1280, xrcode 0, version 0, flags 0