dd50212.kasserver.com has no MX records.
Question and response
Question
dig dd50212.kasserver.com. MX
Answer
The response has no answer records.
Authority
kasserver.com. 3600 SOA ns5.kasserver.com. hostmaster.kasserver.com. 2602240620 28800 7200 1209600 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0