ns2.socio.gs has no MX records.
Question and response
Question
dig ns2.socio.gs. MX
Answer
The response has no answer records.
Authority
socio.gs. 60 SOA ns1.aztecaservicios.com. please_set_email.absolutely.nowhere. 195 10800 3600 2419200 120
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0