Apex domains cannot have CNAME records.
Question and response
Question
dig teccloud.com. NS
Answer
teccloud.com. 4 NS ns2.teccloud.com.br.
teccloud.com. 4 NS ns1.teccloud.com.
Authority
The response has no authority records.
Additional
ns1.teccloud.com. 4 A 201.7.202.249
ns2.teccloud.com.br. 4 A 54.94.180.81
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0