mail.hoston.com.ua has no CNAME records.
Question and response
Question
dig mail.hoston.com.ua. NS
Answer
The response has no answer records.
Authority
com.ua. 1442 SOA ho1.com.ns.ua. dnsmaster.hostmaster.ua. 2008291771 1800 450 1814400 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0