Apex domains cannot have CNAME records.
Question and response
Question
dig inicia.es. NS
Answer
inicia.es. 5 NS dns07.gigas.com.
inicia.es. 5 NS dns08.gigas.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0