Apex domains cannot have CNAME records.
Question and response
Question
dig restaurantenaialanzarote.com. NS
Answer
restaurantenaialanzarote.com. 5 NS ns-702.awsdns-23.net.
restaurantenaialanzarote.com. 5 NS ns-188.awsdns-23.com.
restaurantenaialanzarote.com. 5 NS ns-1513.awsdns-61.org.
restaurantenaialanzarote.com. 5 NS ns-1100.awsdns-09.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0