Apex domains cannot have CNAME records.
Question and response
Question
dig diusframi.es. NS
Answer
diusframi.es. 5 NS dns1.nominalia.com.
diusframi.es. 5 NS dns2.nominalia.com.
Authority
The response has no authority records.
Additional
dns1.nominalia.com. 5 A 81.88.61.3
dns2.nominalia.com. 5 A 81.88.63.48
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0