ip231.ip-51-79-41.net has no MX records.
Question and response
Question
dig ip231.ip-51-79-41.net. MX
Answer
The response has no answer records.
Authority
ip-51-79-41.net. 300 SOA dns10.ovh.ca. tech.ovh.net. 2019013000 86400 3600 3600000 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0