unix1.megared.net.mx has no MX records.
Question and response
Question
dig unix1.megared.net.mx. MX
Answer
The response has no answer records.
Authority
megared.net.mx. 600 SOA ns1.megared.net.mx.megared.net.mx. root.unix.megared.net.mx.megared.net.mx. 1716 3600 900 604800 600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0