ntp1.lwlcom.net has no MX records.
Question and response
Question
dig ntp1.lwlcom.net. MX
Answer
The response has no answer records.
Authority
lwlcom.net. 3600 SOA ns01.lwldns.de. noc.lwlcom.net. 2017013000 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0