help.smarthome.rt.ru has no MX records.
Question and response
Question
dig help.smarthome.rt.ru. MX
Answer
help.smarthome.rt.ru. 4 CNAME help.smarthome.soib.rt.ru.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0