Apex domains cannot have CNAME records.
Question and response
Question
dig insurethathorse.com. NS
Answer
insurethathorse.com. 5 NS ns1.insurethathorse.com.
insurethathorse.com. 5 NS ns2.insurethathorse.com.
Authority
The response has no authority records.
Additional
ns1.insurethathorse.com. 5 A 38.180.85.123
ns2.insurethathorse.com. 5 A 38.244.144.171
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0