smtp-spb-00.OBIT.RU has no MX records.
Question and response
Question
dig smtp-spb-00.OBIT.RU. MX
Answer
The response has no answer records.
Authority
OBIT.RU. 3600 SOA dns1.OBIT.RU. dns.OBIT.RU. 2026030604 3600 3600 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0