mail.icloudtech.ru has no CNAME records.
Question and response
Question
dig mail.icloudtech.ru. NS
Answer
The response has no answer records.
Authority
icloudtech.ru. 7730 SOA ns1.mastertel.ru. noc.mastertel.ru. 2025070800 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0