mail.cityemail.com has no MX records.
Question and response
Question
dig mail.cityemail.com. MX
Answer
The response has no answer records.
Authority
cityemail.com. 3600 SOA ns3.linuxmagic.com. hostmaster.wizard.ca. 408 21600 3600 604800 43200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0