Apex domains cannot have CNAME records.
Question and response
Question
dig ocpdns.com. NS
Answer
ocpdns.com. 4 NS ns.ocpdns.com.
Authority
The response has no authority records.
Additional
ns.ocpdns.com. 4 A 43.224.137.7
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0