Apex domains cannot have CNAME records.
Question and response
Question
dig openip-cs.net. NS
Answer
openip-cs.net. 4 NS ns2.destiny.be.
openip-cs.net. 4 NS ns1.destiny.be.
openip-cs.net. 4 NS ns4.destiny.eu.
openip-cs.net. 4 NS ns3.destiny.eu.
Authority
The response has no authority records.
Additional
ns1.destiny.be. 4 A 85.158.210.70
ns2.destiny.be. 4 A 95.142.165.111
ns3.destiny.eu. 4 A 192.174.68.118
ns4.destiny.eu. 4 A 176.97.158.118
ns3.destiny.eu. 4 AAAA 2001:67c:1bc:0:0:0:0:118
ns4.destiny.eu. 4 AAAA 2001:67c:10b8:0:0:0:0:118
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0