ns.ru1.USERECHO.RU has no MX records.
Question and response
Question
dig ns.ru1.USERECHO.RU. MX
Answer
The response has no answer records.
Authority
USERECHO.RU. 600 SOA ns.ru1.USERECHO.RU. info.USERECHO.RU. 1257583654 300 360 604800 38400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0