dnsadm-interno.uninet.net.mx.telnor.net has no MX records.
Question and response
Question
dig dnsadm-interno.uninet.net.mx.telnor.net. MX
Answer
The response has no answer records.
Authority
telnor.net. 900 SOA dnsadm-interno.uninet.net.mx.telnor.net. dns-adm.reduno.com.mx.telnor.net. 2019040412 10800 3600 604800 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0