www.tucowsdomains.com has no MX records.
Question and response
Question
dig www.tucowsdomains.com. MX
Answer
The response has no answer records.
Authority
tucowsdomains.com. 300 SOA ns1.tucows.com. hostmaster.systemdns.com. 1772668800 10800 3600 2592000 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0