Apex domains cannot have CNAME records.
Question and response
Question
dig supportsystem.com. NS
Answer
supportsystem.com. 3 NS ns-951.awsdns-54.net.
supportsystem.com. 3 NS ns-1700.awsdns-20.co.uk.
supportsystem.com. 3 NS ns-83.awsdns-10.com.
supportsystem.com. 3 NS ns-1304.awsdns-35.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0