Apex domains cannot have CNAME records.
Question and response
Question
dig 5nine.com. NS
Answer
5nine.com. 2 NS ns-1433.awsdns-51.org.
5nine.com. 2 NS ns-1017.awsdns-63.net.
5nine.com. 2 NS ns-492.awsdns-61.com.
5nine.com. 2 NS ns-1881.awsdns-43.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0