ps.staging.oml.RU has no MX records.
Question and response
Question
dig psapi.megagroup.RU. MX
Answer
The response has no answer records.
Authority
megagroup.RU. 2900 SOA ns1.megagroup.RU. dnsmaster.megagroup.RU. 2026022001 21600 1800 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0