Apex domains cannot have CNAME records.
Question and response
Question
dig a-z-shop.com. NS
Answer
a-z-shop.com. 5 NS ns-901.awsdns-48.net.
a-z-shop.com. 5 NS ns-215.awsdns-26.com.
a-z-shop.com. 5 NS ns-350.awsdns-43.com.
a-z-shop.com. 5 NS ns-1189.awsdns-20.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0