Apex domains cannot have CNAME records.
Question and response
Question
dig nfon.com. NS
Answer
nfon.com. 5 NS a.myradns.net.
nfon.com. 5 NS b.myradns.net.
nfon.com. 5 NS c.myradns.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0