dns.gemtel.com.mx has no CNAME records.
Question and response
Question
dig dns.gemtel.com.mx. NS
Answer
The response has no answer records.
Authority
gemtel.com.mx. 10800 SOA ns1.gemtel.com.mx. noc.yuvox.net. 2025123101 3600 1800 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0