Apex domains cannot have CNAME records.
Question and response
Question
dig uncu.edu.ar. NS
Answer
uncu.edu.ar. 5 NS raiz.uncu.edu.ar.
uncu.edu.ar. 5 NS nok-3945.uncu.edu.ar.
uncu.edu.ar. 5 NS nok-3845.uncu.edu.ar.
uncu.edu.ar. 5 NS ns1.riu.edu.ar.
uncu.edu.ar. 5 NS noc.uncu.edu.ar.
uncu.edu.ar. 5 NS zonda.uncu.edu.ar.
Authority
The response has no authority records.
Additional
noc.uncu.edu.ar. 5 A 170.210.2.97
raiz.uncu.edu.ar. 5 A 200.9.147.34
zonda.uncu.edu.ar. 5 A 170.210.45.117
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0