Apex domains cannot have CNAME records.
Question and response
Question
dig dns-servicios.com. NS
Answer
dns-servicios.com. 5 NS ns2.hostalia.com.
dns-servicios.com. 5 NS ns.hostalia.com.
Authority
The response has no authority records.
Additional
ns.hostalia.com. 5 A 82.194.64.30
ns2.hostalia.com. 5 A 82.194.80.30
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0