Apex domains cannot have CNAME records.
Question and response
Question
dig telecentro.com.ar. NS
Answer
telecentro.com.ar. 5 NS ns2.telecentro.net.ar.
telecentro.com.ar. 5 NS ns3.telecentro.net.ar.
telecentro.com.ar. 5 NS ns1.telecentro.net.ar.
Authority
The response has no authority records.
Additional
ns1.telecentro.net.ar. 5 A 200.115.194.137
ns2.telecentro.net.ar. 5 A 200.115.193.253
ns3.telecentro.net.ar. 5 A 54.243.235.48
ns1.telecentro.net.ar. 5 AAAA 2800:810:100:0:0:0:0:1
ns2.telecentro.net.ar. 5 AAAA 2800:810:120:0:0:0:0:1
ns3.telecentro.net.ar. 5 AAAA 2600:1f18:2352:7701:5832:1124:6e60:f7a5
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0