Apex domains cannot have CNAME records.
Question and response
Question
dig network.cyso.net. NS
Answer
network.cyso.net. 5 NS anycast-global.dns.cyso.net.
network.cyso.net. 5 NS unicast-eu.dns.cyso.nl.
network.cyso.net. 5 NS anycast-eu.dns.cyso.eu.
Authority
The response has no authority records.
Additional
anycast-eu.dns.cyso.eu. 5 A 194.58.196.57
unicast-eu.dns.cyso.nl. 5 A 185.42.137.109
anycast-global.dns.cyso.net. 5 A 194.58.198.57
anycast-eu.dns.cyso.eu. 5 AAAA 2a01:3f1:857:0:0:0:0:53
unicast-eu.dns.cyso.nl. 5 AAAA 2a01:3f0:400:0:0:0:0:57
anycast-global.dns.cyso.net. 5 AAAA 2a01:3f1:3057:0:0:0:0:53
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0