Apex domains cannot have CNAME records.
Question and response
Question
dig potton-delph.com. NS
Answer
potton-delph.com. 5 NS ns-1962.awsdns-53.co.uk.
potton-delph.com. 5 NS ns-129.awsdns-16.com.
potton-delph.com. 5 NS ns-427.awsdns-53.com.
potton-delph.com. 5 NS ns-1068.awsdns-05.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0