Apex domains cannot have CNAME records.
Question and response
Question
dig belugacdn.com. NS
Answer
belugacdn.com. 2 NS ns1.belugacdn.com.
belugacdn.com. 2 NS ns2.belugacdn.com.
Authority
The response has no authority records.
Additional
ns1.belugacdn.com. 2 A 199.167.64.1
ns2.belugacdn.com. 2 A 104.37.177.1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0