dkim.mcsv.net has no MX records.
Question and response
Question
dig dkim.mcsv.net. MX
Answer
The response has no answer records.
Authority
mcsv.net. 86400 SOA pdns177.ultradns.com. abuse.mailchimp.com. 2013160596 10800 3600 2592000 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0