Apex domains cannot have CNAME records.
Question and response
Question
dig cure.edu.uy. NS
Answer
cure.edu.uy. 5 NS guabiyu.interior.edu.uy.
cure.edu.uy. 5 NS dayman.unorte.edu.uy.
cure.edu.uy. 5 NS arapey.unorte.edu.uy.
cure.edu.uy. 5 NS moza.cure.edu.uy.
cure.edu.uy. 5 NS catanga.interior.edu.uy.
cure.edu.uy. 5 NS anaconda.cure.edu.uy.
Authority
The response has no authority records.
Additional
arapey.unorte.edu.uy. 5 A 164.73.212.2
dayman.unorte.edu.uy. 5 A 164.73.212.3
catanga.interior.edu.uy. 5 A 164.73.98.105
guabiyu.interior.edu.uy. 5 A 164.73.98.9
anaconda.cure.edu.uy. 5 A 164.73.227.7
arapey.unorte.edu.uy. 5 AAAA 2001:1328:1c:0:0:0:212:2
dayman.unorte.edu.uy. 5 AAAA 2001:1328:1c:0:0:0:212:3
catanga.interior.edu.uy. 5 AAAA 2001:1328:6a:0:0:0:0:105
guabiyu.interior.edu.uy. 5 AAAA 2001:1328:6a:0:0:0:0:9
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0