_spf.sgate.mta2.stsender.ru has no MX records.
Question and response
Question
dig _spf.sgate.mta2.stsender.ru. MX
Answer
The response has no answer records.
Authority
stsender.ru. 7200 SOA ns1.nameself.com. support.regtime.net. 1753259044 300 300 604800 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0