ed.shawcable.net has no MX records.
Question and response
Question
dig ed.shawcable.net. MX
Answer
The response has no answer records.
Authority
ed.shawcable.net. 600 SOA ns1.ar.ed.shawcable.net. dnsadmin.shaw.ca. 2250661136 10800 3600 604800 600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0