ns01.netecom.com.br has no CNAME records.
Question and response
Question
dig ns01.netecom.com.br. NS
Answer
The response has no answer records.
Authority
netecom.com.br. 3600 SOA ns01.netecom.com.br. admin.netecom.com.br. 2026022508 10800 900 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0