Apex domains cannot have CNAME records.
Question and response
Question
dig zycus.com. NS
Answer
zycus.com. 5 NS a2-64.akam.net.
zycus.com. 5 NS a11-67.akam.net.
zycus.com. 5 NS a9-67.akam.net.
zycus.com. 5 NS a1-16.akam.net.
zycus.com. 5 NS a28-65.akam.net.
zycus.com. 5 NS a6-66.akam.net.
Authority
The response has no authority records.
Additional
a11-67.akam.net. 2 A 84.53.139.67
a11-67.akam.net. 2 AAAA 2600:1480:1:0:0:0:0:43
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0