Apex domains cannot have CNAME records.
Question and response
Question
dig coredial.com. NS
Answer
coredial.com. 5 NS ns-1471.awsdns-55.org.
coredial.com. 5 NS ns-959.awsdns-55.net.
coredial.com. 5 NS ns-415.awsdns-51.com.
coredial.com. 5 NS ns-1782.awsdns-30.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0