mail.radier.ca has no CNAME records.
Question and response
Question
dig mail.radier.ca. NS
Answer
The response has no answer records.
Authority
radier.ca. 3600 SOA www.radier.ca. root.radier.ca. 20221016 7200 7200 7200 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0