Apex domains cannot have CNAME records.
Question and response
Question
dig rdstation.com.br. NS
Answer
rdstation.com.br. 5 NS ns-1862.awsdns-40.co.uk.
rdstation.com.br. 5 NS ns-608.awsdns-12.net.
rdstation.com.br. 5 NS ns-132.awsdns-16.com.
rdstation.com.br. 5 NS ns-1491.awsdns-58.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0