mm.fr.colt.net has no MX records.
Question and response
Question
dig mm.fr.colt.net. MX
Answer
The response has no answer records.
Authority
mm.fr.colt.net. 3600 SOA ns0.coltfrance.com. hostmaster.coltfrance.com. 2017020800 21600 3600 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0