mx3.controldeservidor.com has no MX records.
Question and response
Question
dig mx3.controldeservidor.com. MX
Answer
The response has no answer records.
Authority
controldeservidor.com. 3600 SOA ns1.controldeservidor.com. servidores.loading.es. 2025112501 10800 3600 604800 10800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0