Apex domains cannot have CNAME records.
Question and response
Question
dig garnethill.com. NS
Answer
garnethill.com. 5 NS a11-66.akam.net.
garnethill.com. 5 NS a1-21.akam.net.
garnethill.com. 5 NS a3-64.akam.net.
garnethill.com. 5 NS a6-65.akam.net.
garnethill.com. 5 NS a8-66.akam.net.
garnethill.com. 5 NS a26-67.akam.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0