fmdkim.net has no MX records.
Question and response
Question
dig fmdkim.net. MX
Answer
The response has no answer records.
Authority
fmdkim.net. 300 SOA ns1.flowmailer.net. contact.flowmailer.net. 2603100910 300 600 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0