plesk.esoo.ru has no MX records.
Question and response
Question
dig ns4.esoo.ru. MX
Answer
The response has no answer records.
Authority
esoo.ru. 10800 SOA ns1.esoo.ru. hostmaster.esoo.ru. 2025111800 43200 7200 360000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0