dns1.st1internet.com.br has no CNAME records.
Question and response
Question
dig dns1.st1internet.com.br. NS
Answer
The response has no answer records.
Authority
st1internet.com.br. 300 SOA dns1.st1internet.com.br. noc.st1.net.br. 2026030606 3600 600 1209600 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0