Apex domains cannot have CNAME records.
Question and response
Question
dig grupoh4.com. NS
Answer
grupoh4.com. 5 NS ns-99.awsdns-12.com.
grupoh4.com. 5 NS ns-925.awsdns-51.net.
grupoh4.com. 5 NS ns-1187.awsdns-20.org.
grupoh4.com. 5 NS ns-1224.awsdns-25.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0