Apex domains cannot have CNAME records.
Question and response
Question
dig dnsserver8.com. NS
Answer
dnsserver8.com. 2 NS ns1.dnsserver8.com.
dnsserver8.com. 2 NS ns2.dnsserver8.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0