Apex domains cannot have CNAME records.
Question and response
Question
dig cyon.net. NS
Answer
cyon.net. 5 NS ns2.cyon.ch.
cyon.net. 5 NS ns1.cyon.ch.
Authority
The response has no authority records.
Additional
ns1.cyon.ch. 5 A 185.174.216.2
ns2.cyon.ch. 5 A 91.206.24.2
ns1.cyon.ch. 5 AAAA 2a01:ab20:0:185:0:0:0:2
ns2.cyon.ch. 5 AAAA 2001:67c:234:0:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0