Apex domains cannot have CNAME records.
Question and response
Question
dig next-data.net. NS
Answer
next-data.net. 5 NS dns2.next-data.net.
next-data.net. 5 NS dns1.next-data.net.
Authority
The response has no authority records.
Additional
dns1.next-data.net. 5 A 185.124.45.250
dns2.next-data.net. 5 A 51.255.211.27
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0