mail.guna.com.mx has no NS records.
NS records for this zone are defined at guna.com.mx.
NS records for this zone are defined at guna.com.mx.
Question and response
Question
dig mail.guna.com.mx. NS
Answer
The response has no answer records.
Authority
guna.com.mx. 1800 SOA donna.ns.cloudflare.com. dns.cloudflare.com. 2397286539 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0