Apex domains cannot have CNAME records.
Question and response
Question
dig codero.com. NS
Answer
codero.com. 4 NS ns2.codero.com.
codero.com. 4 NS ns1.codero.com.
Authority
The response has no authority records.
Additional
ns1.codero.com. 4 A 18.209.216.105
ns2.codero.com. 4 A 69.64.66.6
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0