k3._domainkey.virtutel.com.au has no MX records.
Question and response
Question
dig dkim3.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