ns1.bsi.com.br has no CNAME records.
Question and response
Question
dig ns1.bsi.com.br. NS
Answer
The response has no answer records.
Authority
bsi.com.br. 7718 SOA ns1.bsi.com.br. root.dedi.4296494.bsi.com.br. 2026022501 3600 1800 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0