mail.nlmp01.net has no MX records.
Question and response
Question
dig mail.nlmp01.net. MX
Answer
The response has no answer records.
Authority
nlmp01.net. 300 SOA level.np6.com. masterdns.np6.com. 2005040547 900 600 86400 300
Additional
. 0 OPT ; payload 4000, xrcode 0, version 0, flags 0