Apex domains cannot have CNAME records.
Question and response
Question
dig ztomy.com. NS
Answer
ztomy.com. 5 NS a22-64.akam.net.
ztomy.com. 5 NS a13-67.akam.net.
ztomy.com. 5 NS eur6.akam.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0