ns1.dnscheck.com.ar has no CNAME records.
Question and response
Question
dig ns1.dnscheck.com.ar. NS
Answer
The response has no answer records.
Authority
dnscheck.com.ar. 2238 SOA ns1.allytech.com. root.dnscheck.com.ar. 2024041349 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0