a.ns.bigleaf.net has no MX records.
Question and response
Question
dig a.ns.bigleaf.net. MX
Answer
The response has no answer records.
Authority
bigleaf.net. 600 SOA bigleaf.net. admin.bigleaf.net. 1771372800 3600 120 604800 600
Additional
. 0 OPT ; payload 1680, xrcode 0, version 0, flags 0