mx0.mail4.freehost.com.ua has no CNAME records.
Question and response
Question
dig mx0.mail4.freehost.com.ua. NS
Answer
The response has no answer records.
Authority
freehost.com.ua. 3436 SOA alpha.freehost.com.ua. domainmaster.dns82.net. 2019112701 14400 600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0