Apex domains cannot have CNAME records.
Question and response
Question
dig firstclass-casinos.com. NS
Answer
firstclass-casinos.com. 5 NS ns-50.awsdns-06.com.
firstclass-casinos.com. 5 NS ns-1063.awsdns-04.org.
firstclass-casinos.com. 5 NS ns-847.awsdns-41.net.
firstclass-casinos.com. 5 NS ns-1415.awsdns-48.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0