Apex domains cannot have CNAME records.
Question and response
Question
dig radiant.net. NS
Answer
radiant.net. 5 NS dns60.telus.com.
radiant.net. 5 NS dns60.telus.ca.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0