Apex domains cannot have CNAME records.
Question and response
Question
dig meucartaotricard.com.br. NS
Answer
meucartaotricard.com.br. 5 NS ns-312.awsdns-39.com.
meucartaotricard.com.br. 5 NS ns-2037.awsdns-62.co.uk.
meucartaotricard.com.br. 5 NS ns-1253.awsdns-28.org.
meucartaotricard.com.br. 5 NS ns-517.awsdns-00.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0