mail.china-courier.com has no MX records.
Question and response
Question
dig mail.china-courier.com. MX
Answer
The response has no answer records.
Authority
china-courier.com. 3600 SOA ns1.tecnisoft.hn. crg.wicom-telefonica.com. 1741892369 3600 600 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0