Apex domains cannot have CNAME records.
Question and response
Question
dig cmmc-hk.org. NS
Answer
cmmc-hk.org. 5 NS ns-1358.awsdns-41.org.
cmmc-hk.org. 5 NS ns-834.awsdns-40.net.
cmmc-hk.org. 5 NS ns-54.awsdns-06.com.
cmmc-hk.org. 5 NS ns-467.awsdns-58.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0