mirrors.24HC.RU has no MX records.
Question and response
Question
dig mirrors.24HC.RU. MX
Answer
The response has no answer records.
Authority
24HC.RU. 60 SOA isp.24HC.RU. info.itcom.info. 2017052253 60 3600 604800 86400
Additional
. 0 OPT ; payload 1680, xrcode 0, version 0, flags 0