ns3.lightningwirelabs.com has no MX records.
Question and response
Question
dig ns3.lightningwirelabs.com. MX
Answer
The response has no answer records.
Authority
lightningwirelabs.com. 600 SOA master.lwldns.net. hostmaster\@lightningwirelabs.com. 2026024937 10800 1800 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0