Apex domains cannot have CNAME records.
Question and response
Question
dig derecho.uncu.edu.ar. NS
Answer
derecho.uncu.edu.ar. 4 NS ns1.derecho.uncu.edu.ar.
Authority
The response has no authority records.
Additional
ns1.derecho.uncu.edu.ar. 4 A 200.12.133.194
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0