mx.caravan.ru has no CNAME records.
Question and response
Question
dig mx.caravan.ru. NS
Answer
The response has no answer records.
Authority
caravan.ru. 156 SOA sns1.rsnx.ru. noc.caravan.ru. 2024101586 14400 7200 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0