mailing.whc.ca has no MX records.
Question and response
Question
dig mailing.whc.ca. MX
Answer
The response has no answer records.
Authority
whc.ca. 1800 SOA coleman.ns.cloudflare.com. dns.cloudflare.com. 2397018560 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0