Apex domains cannot have CNAME records.
Question and response
Question
dig docredington.com. NS
Answer
docredington.com. 4 NS ns-1699.awsdns-20.co.uk.
docredington.com. 4 NS ns-331.awsdns-41.com.
docredington.com. 4 NS ns-697.awsdns-23.net.
docredington.com. 4 NS ns-920.awsdns-51.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0