Apex domains cannot have CNAME records.
Question and response
Question
dig smartprotools.com. NS
Answer
smartprotools.com. 3 NS ns2.dyna-ns.net.
smartprotools.com. 3 NS ns1.dyna-ns.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0