corp-fw-1.longlines.com has no MX records.
Question and response
Question
dig corp-fw-1.longlines.com. MX
Answer
The response has no answer records.
Authority
longlines.com. 3600 SOA ns1.longlines.com. postmaster.longlines.com. 721599979 7200 3600 1728000 14400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0