mail.cls-communication.com has no MX records.
Question and response
Question
dig mail.cls-communication.com. MX
Answer
The response has no answer records.
Authority
cls-communication.com. 600 SOA ns77.domaincontrol.com. dns.jomax.net. 2025021004 28800 7200 604800 600
Additional
. 0 OPT ; payload 1280, xrcode 0, version 0, flags 0