ns2.init7.net has no MX records.
Question and response
Question
dig ns2.init7.net. MX
Answer
The response has no answer records.
Authority
init7.net. 777 SOA ns1.init7.net. hostmaster.init7.net. 2026020500 1200 900 604800 777
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0