mail.pfr.ru has no MX records.
Question and response
Question
dig mail.pfr.ru. MX
Answer
The response has no answer records.
Authority
pfr.ru. 3600 SOA nsmt.rt.ru. hostmaster.pfr.ru. 1730821232 43200 3600 1814400 3600
Additional
. 0 OPT ; payload 512, xrcode 0, version 0, flags 0