relay04.na.intgdc.com has no MX records.
Question and response
Question
dig relay04.na.intgdc.com. MX
Answer
The response has no answer records.
Authority
na.intgdc.com. 60 SOA dns1.p06.nsone.net. hostmaster.nsone.net. 1654591155 600 300 1209600 60
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0