Apex domains cannot have CNAME records.
Question and response
Question
dig huronclick.com. NS
Answer
huronclick.com. 5 NS ns-1560.awsdns-03.co.uk.
huronclick.com. 5 NS ns-209.awsdns-26.com.
huronclick.com. 5 NS ns-638.awsdns-15.net.
huronclick.com. 5 NS ns-1268.awsdns-30.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0