nsmty2.uninet.net.mx has no MX records.
Question and response
Question
dig nsmty2.uninet.net.mx. MX
Answer
The response has no answer records.
Authority
uninet.net.mx. 900 SOA dnsadm-interno.uninet.net.mx. adm-dns.reduno.com.mx. 11005 14400 3600 604800 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0