ns2.obcity.RU has no MX records.
Question and response
Question
dig ns2.obcity.RU. MX
Answer
The response has no answer records.
Authority
obcity.RU. 10800 SOA ns.obcity.RU. ns1.obcity.RU. 2012020920 43200 3600 1209600 10800
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0