mta-005.msdp1.com has no MX records.
Question and response
Question
dig mta-005.msdp1.com. MX
Answer
The response has no answer records.
Authority
msdp1.com. 14400 SOA ns1.msdp1.com. hostmaster.msdp1.com. 2 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0