Apex domains cannot have CNAME records.
Question and response
Question
dig fleamarketwarehouse.com. NS
Answer
fleamarketwarehouse.com. 4 NS ns-1420.awsdns-49.org.
fleamarketwarehouse.com. 4 NS ns-365.awsdns-45.com.
fleamarketwarehouse.com. 4 NS ns-442.awsdns-55.com.
fleamarketwarehouse.com. 4 NS ns-1087.awsdns-07.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0