Apex domains cannot have CNAME records.
Question and response
Question
dig corenap.com. NS
Answer
corenap.com. 4 NS ns1.dfw.databank.com.
corenap.com. 4 NS ns2.slc.databank.com.
corenap.com. 4 NS ns1.msp.databank.com.
corenap.com. 4 NS ns2.dfw.databank.com.
corenap.com. 4 NS ns1.slc.databank.com.
corenap.com. 4 NS ns2.iad.databank.com.
corenap.com. 4 NS ns2.msp.databank.com.
corenap.com. 4 NS ns1.iad.databank.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0