_netblocks.hostmaster.ua has no CNAME records.
Question and response
Question
dig _netblocks.hostmaster.ua. NS
Answer
The response has no answer records.
Authority
hostmaster.ua. 1549 SOA ho1.ns.hostmaster.ua. dnsmaster.hostmaster.ua. 2026022400 3636 1818 1814181 1818
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0