Apex domains cannot have CNAME records.
Question and response
Question
dig n-multimidia.com.br. NS
Answer
n-multimidia.com.br. 5 NS ns2.n-multimidia.com.br.
n-multimidia.com.br. 5 NS ns1.n-multimidia.com.br.
Authority
The response has no authority records.
Additional
ns1.n-multimidia.com.br. 5 A 168.0.96.26
ns2.n-multimidia.com.br. 5 A 168.0.96.27
ns1.n-multimidia.com.br. 5 AAAA 2804:2cac:0:0:168:0:96:26
ns2.n-multimidia.com.br. 5 AAAA 2804:2cac:0:0:168:0:96:27
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0