Apex domains cannot have CNAME records.
Question and response
Question
dig trewerne.com. NS
Answer
trewerne.com. 5 NS ns2.trewerne.com.
trewerne.com. 5 NS ns1.trewerne.com.
Authority
The response has no authority records.
Additional
ns1.trewerne.com. 5 A 170.130.206.142
ns2.trewerne.com. 5 A 50.3.109.30
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0