Apex domains cannot have CNAME records.
Question and response
Question
dig damsu.uncu.edu.ar. NS
Answer
damsu.uncu.edu.ar. 4 NS zonda.uncu.edu.ar.
damsu.uncu.edu.ar. 4 NS ns2.damsu.uncu.edu.ar.
damsu.uncu.edu.ar. 4 NS ns1.damsu.uncu.edu.ar.
Authority
The response has no authority records.
Additional
ns1.damsu.uncu.edu.ar. 4 A 200.9.147.34
ns2.damsu.uncu.edu.ar. 4 A 170.210.2.97
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0