Apex domains cannot have CNAME records.
Question and response
Question
dig dns-siteserver.com. NS
Answer
dns-siteserver.com. 4 NS ns-1086.awsdns-07.org.
dns-siteserver.com. 4 NS ns-91.awsdns-11.com.
dns-siteserver.com. 4 NS ns-681.awsdns-21.net.
dns-siteserver.com. 4 NS ns-1466.awsdns-55.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0