ymbk.com has no MX records.
Question and response
Question
dig ymbk.com. MX
Answer
The response has no answer records.
Authority
ymbk.com. 14400 SOA rip.psg.com. hostmaster.psg.com. 1771598429 86400 3600 2592000 14400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0