mx.spamdam.ca has no CNAME records.
Question and response
Question
dig mx.spamdam.ca. NS
Answer
The response has no answer records.
Authority
spamdam.ca. 3384 SOA dns.spamdam.ca. hostmaster.spamdam.ca. 1618476119 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0