18.31-pool.datagroup.com.ua has no CNAME records.
Question and response
Question
dig 18.31-pool.datagroup.com.ua. NS
Answer
The response has no answer records.
Authority
datagroup.com.ua. 3225 SOA ns.newline.net.ua. hostmaster.newline.net.ua. 2023122100 28800 7200 2419200 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0