Apex domains cannot have CNAME records.
Question and response
Question
dig nic.uy. NS
Answer
nic.uy. 5 NS a.nic.uy.
nic.uy. 5 NS b.nic.uy.
Authority
The response has no authority records.
Additional
a.nic.uy. 5 A 164.73.128.5
b.nic.uy. 5 A 164.73.128.70
a.nic.uy. 5 AAAA 2001:1328:6:0:0:0:0:5
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0