emx.mail.RU has no CNAME records.
Question and response
Question
dig emx.mail.RU. NS
Answer
The response has no answer records.
Authority
mail.RU. 60 SOA ns1.mail.RU. hostmaster.mail.RU. 3563985577 900 900 604800 60
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0