sys.init7.net has no MX records.
Question and response
Question
dig sys.init7.net. MX
Answer
The response has no answer records.
Authority
sys.init7.net. 777 SOA ns1.init7.net. hostmaster.init7.net. 2026021600 1200 360 1209600 777
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0