Apex domains cannot have CNAME records.
Question and response
Question
dig cablevision.net.mx. NS
Answer
cablevision.net.mx. 3 NS ns02-s02.izzi.mx.
cablevision.net.mx. 3 NS cvdnsisp4.cablevision.net.mx.
cablevision.net.mx. 3 NS ns02-s01.izzi.mx.
Authority
The response has no authority records.
Additional
cvdnsisp4.cablevision.net.mx. 3 A 200.77.160.130
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0