Apex domains cannot have CNAME records.
Question and response
Question
dig atriasouthsetauket.com. NS
Answer
atriasouthsetauket.com. 5 NS ns-10.awsdns-01.com.
atriasouthsetauket.com. 5 NS ns-2027.awsdns-61.co.uk.
atriasouthsetauket.com. 5 NS ns-1361.awsdns-42.org.
atriasouthsetauket.com. 5 NS ns-140.awsdns-17.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0