Apex domains cannot have CNAME records.
Question and response
Question
dig telesp.net.br. NS
Answer
telesp.net.br. 4 NS orion.vivo.com.br.
telesp.net.br. 4 NS lynx.vivo.com.br.
telesp.net.br. 4 NS hercules.vivo.com.br.
telesp.net.br. 4 NS aquarius.vivo.com.br.
Authority
The response has no authority records.
Additional
lynx.vivo.com.br. 4 A 189.19.56.230
orion.vivo.com.br. 4 A 177.79.237.231
aquarius.vivo.com.br. 4 A 189.19.56.226
hercules.vivo.com.br. 4 A 177.79.237.228
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0