Apex domains cannot have CNAME records.
Question and response
Question
dig 97stone.com. NS
Answer
97stone.com. 5 NS ns-569.awsdns-07.net.
97stone.com. 5 NS ns-489.awsdns-61.com.
97stone.com. 5 NS ns-264.awsdns-33.com.
97stone.com. 5 NS ns-1138.awsdns-14.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0