Apex domains cannot have CNAME records.
Question and response
Question
dig h-email.net. NS
Answer
h-email.net. 5 NS ns-1600.awsdns-08.co.uk.
h-email.net. 5 NS ns-786.awsdns-34.net.
h-email.net. 5 NS ns-483.awsdns-60.com.
h-email.net. 5 NS ns-1197.awsdns-21.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0