dns04.cogeco.net has no MX records.
Question and response
Question
dig dns04.cogeco.net. MX
Answer
The response has no answer records.
Authority
cogeco.net. 300 SOA ns1.cgocable.net. dnsadmin.cgocable.net. 2008205298 1800 900 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0