mx1.dfw.automattic.com has no MX records.
Question and response
Question
dig mx1.dfw.automattic.com. MX
Answer
The response has no answer records.
Authority
automattic.com. 60 SOA ns1.automattic.com. hostmaster.automattic.com. 2023091834 14400 7200 604800 60
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0