Apex domains cannot have CNAME records.
Question and response
Question
dig radier.ca. NS
Answer
radier.ca. 4 NS mail.radier.ca.
Authority
The response has no authority records.
Additional
mail.radier.ca. 4 A 142.54.191.236
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0