Apex domains cannot have CNAME records.
Question and response
Question
dig sleepapneacoach.com. NS
Answer
sleepapneacoach.com. 5 NS ns1.sleepapneacoach.com.
sleepapneacoach.com. 5 NS ns2.sleepapneacoach.com.
Authority
The response has no authority records.
Additional
ns1.sleepapneacoach.com. 5 A 5.61.58.181
ns2.sleepapneacoach.com. 5 A 208.115.207.68
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0