Apex domains cannot have CNAME records.
Question and response
Question
dig rantom-sporris.com. NS
Answer
rantom-sporris.com. 5 NS ns-405.awsdns-50.com.
rantom-sporris.com. 5 NS ns-1690.awsdns-19.co.uk.
rantom-sporris.com. 5 NS ns-902.awsdns-48.net.
rantom-sporris.com. 5 NS ns-1894.awsdns-44.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0