Apex domains cannot have CNAME records.
Question and response
Question
dig unorte.edu.uy. NS
Answer
unorte.edu.uy. 4 NS seciu.edu.uy.
unorte.edu.uy. 4 NS dayman.unorte.edu.uy.
unorte.edu.uy. 4 NS arapey.unorte.edu.uy.
Authority
The response has no authority records.
Additional
seciu.edu.uy. 4 A 164.73.128.5
arapey.unorte.edu.uy. 4 A 164.73.212.2
dayman.unorte.edu.uy. 4 A 164.73.212.3
arapey.unorte.edu.uy. 4 AAAA 2001:1328:1c:0:0:0:212:2
dayman.unorte.edu.uy. 4 AAAA 2001:1328:1c:0:0:0:212:3
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0