Apex domains cannot have CNAME records.
Question and response
Question
dig cyberlink.ch. NS
Answer
cyberlink.ch. 1 NS ns2.cyberlink.ch.
cyberlink.ch. 1 NS ns3.cyberlink.ch.
cyberlink.ch. 1 NS ns1.cyberlink.ch.
Authority
The response has no authority records.
Additional
ns1.cyberlink.ch. 1 A 62.12.130.28
ns2.cyberlink.ch. 1 A 193.246.253.194
ns3.cyberlink.ch. 1 A 213.144.148.42
ns1.cyberlink.ch. 2 AAAA 2001:8a8:1818:1:0:0:0:28
ns2.cyberlink.ch. 2 AAAA 2001:8a8:1818:2:0:0:0:194
ns3.cyberlink.ch. 2 AAAA 2001:1620:2018:0:0:0:0:42
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0