Apex domains cannot have CNAME records.
Question and response
Question
dig cosentry.com. NS
Answer
cosentry.com. 5 NS dns4.cosentry.com.
cosentry.com. 5 NS dns3.cosentry.com.
cosentry.com. 5 NS dns1.cosentry.com.
cosentry.com. 5 NS dns2.cosentry.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0