Apex domains cannot have CNAME records.
Question and response
Question
dig ir-static.anteldata.net.uy. NS
Answer
ir-static.anteldata.net.uy. 4 NS ns2.anteldata.com.uy.
ir-static.anteldata.net.uy. 4 NS ns1.anteldata.com.uy.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0