ssl.sonicsecuremail.eu has no MX records.
Question and response
Question
dig ssl.sonicsecuremail.eu. MX
Answer
The response has no answer records.
Authority
sonicsecuremail.eu. 86400 SOA pdns1.ultradns.net. itops.sonicwall.com. 2017021032 86400 86400 86400 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0