Apex domains cannot have CNAME records.
Question and response
Question
dig celticgrovecottages.com. NS
Answer
celticgrovecottages.com. 1 NS ns-836.awsdns-40.net.
celticgrovecottages.com. 1 NS ns-796.awsdns-35.net.
celticgrovecottages.com. 1 NS ns-399.awsdns-49.com.
celticgrovecottages.com. 1 NS ns-754.awsdns-30.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0