mars.doreo.com has no MX records.
Question and response
Question
dig mars.doreo.com. MX
Answer
The response has no answer records.
Authority
doreo.com. 300 SOA dns1.name-services.com. info.name-services.com. 1728912323 172800 900 1814400 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0