Apex domains cannot have CNAME records.
Question and response
Question
dig cobranzaprolegal.com.mx. NS
Answer
cobranzaprolegal.com.mx. 5 NS dns.cobranzaprolegal.com.mx.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0