Apex domains cannot have CNAME records.
Question and response
Question
dig gandalf.evsis.com. NS
Answer
gandalf.evsis.com. 5 NS ns3.evsis.com.ar.
gandalf.evsis.com. 5 NS ns1.evsis.com.ar.
gandalf.evsis.com. 5 NS ns2.evsis.com.ar.
Authority
The response has no authority records.
Additional
ns1.evsis.com.ar. 4 A 190.104.208.3
ns2.evsis.com.ar. 4 A 190.104.197.247
ns3.evsis.com.ar. 4 A 169.47.28.50
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0