Apex domains cannot have CNAME records.
Question and response
Question
dig syndeorestaurante.com. NS
Answer
syndeorestaurante.com. 5 NS ns-170.awsdns-21.com.
syndeorestaurante.com. 5 NS ns-1377.awsdns-44.org.
syndeorestaurante.com. 5 NS ns-1603.awsdns-08.co.uk.
syndeorestaurante.com. 5 NS ns-1611.awsdns-09.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0