Apex domains cannot have CNAME records.
Question and response
Question
dig prod. NS
Answer
prod. 5 NS ns-tld2.charlestonroadregistry.com.
prod. 5 NS ns-tld4.charlestonroadregistry.com.
prod. 5 NS ns-tld5.charlestonroadregistry.com.
prod. 5 NS ns-tld1.charlestonroadregistry.com.
prod. 5 NS ns-tld3.charlestonroadregistry.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0