Apex domains cannot have CNAME records.
Question and response
Question
dig do-sea.com. NS
Answer
do-sea.com. 4 NS ns70.domaincontrol.com.
do-sea.com. 4 NS ns69.domaincontrol.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0