Apex domains cannot have CNAME records.
Question and response
Question
dig terradotta.com. NS
Answer
terradotta.com. 5 NS ns-1385.awsdns-45.org.
terradotta.com. 5 NS ns-1941.awsdns-50.co.uk.
terradotta.com. 5 NS ns-39.awsdns-04.com.
terradotta.com. 5 NS ns-562.awsdns-06.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0