Apex domains cannot have CNAME records.
Question and response
Question
dig houseti.com.br. NS
Answer
houseti.com.br. 4 NS NS2.dnsseconline.com.
houseti.com.br. 4 NS NS1.dnsseconline.com.
houseti.com.br. 4 NS NS3.dnsseconline.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0