ping0.ru has no MX records.
Question and response
Question
dig ping0.ru. MX
Answer
The response has no answer records.
Authority
ping0.ru. 3600 SOA dns1.zolotoff.ru. hostmaster. 45 900 600 86400 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0