Apex domains cannot have CNAME records.
Question and response
Question
dig ingenieria.uncu.edu.ar. NS
Answer
ingenieria.uncu.edu.ar. 5 NS ns.ingenieria.uncuyo.edu.ar.
ingenieria.uncu.edu.ar. 5 NS ns1.ingenieria.uncuyo.edu.ar.
ingenieria.uncu.edu.ar. 5 NS ns2.ingenieria.uncuyo.edu.ar.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0