Apex domains cannot have CNAME records.
Question and response
Question
dig server02.clouddrive.com.br. NS
Answer
server02.clouddrive.com.br. 5 NS ns2.cprapid.com.
server02.clouddrive.com.br. 5 NS ns1.cprapid.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0