mx2.unipol.ru has no MX records.
Question and response
Question
dig mx2.unipol.ru. MX
Answer
The response has no answer records.
Authority
unipol.ru. 900 SOA dns1.yandex.net. dns-hosting.yandex.ru. 24 900 90 86400 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0