mail.coolcom.ca has no CNAME records.
Question and response
Question
dig mail.coolcom.ca. NS
Answer
The response has no answer records.
Authority
coolcom.ca. 10017 SOA ns7.coolcom.com. henk1.coolcom.com. 2026011900 3600 1800 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0