Apex domains cannot have CNAME records.
Question and response
Question
dig gregthornejewelry.com. NS
Answer
gregthornejewelry.com. 5 NS ns-650.awsdns-17.net.
gregthornejewelry.com. 5 NS ns-1681.awsdns-18.co.uk.
gregthornejewelry.com. 5 NS ns-520.awsdns-01.net.
gregthornejewelry.com. 5 NS ns-1088.awsdns-08.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0