Apex domains cannot have CNAME records.
Question and response
Question
dig todoahumados.vservers.es. NS
Answer
todoahumados.vservers.es. 5 NS ns1.serviciodns.es.
todoahumados.vservers.es. 5 NS ns2.serviciodns.es.
todoahumados.vservers.es. 5 NS ns3.serviciodns.es.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0