Apex domains cannot have CNAME records.
Question and response
Question
dig unblock-us.com. NS
Answer
unblock-us.com. 5 NS ns-1610.awsdns-09.co.uk.
unblock-us.com. 5 NS ns-1193.awsdns-21.org.
unblock-us.com. 5 NS ns-335.awsdns-41.com.
unblock-us.com. 5 NS ns-935.awsdns-52.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0