Apex domains cannot have CNAME records.
Question and response
Question
dig admejoresseguridadsig.com. NS
Answer
admejoresseguridadsig.com. 5 NS ns-453.awsdns-56.com.
admejoresseguridadsig.com. 5 NS ns-177.awsdns-22.com.
admejoresseguridadsig.com. 5 NS ns-2021.awsdns-60.co.uk.
admejoresseguridadsig.com. 5 NS ns-1352.awsdns-41.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0