ns2.aztecaservicios.com has no MX records.
Question and response
Question
dig ns2.aztecaservicios.com. MX
Answer
The response has no answer records.
Authority
aztecaservicios.com. 900 SOA ns1.aztecaservicios.com. admindomains.aztecaservicios.com. 2008081974 10800 3600 2419200 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0