Apex domains cannot have CNAME records.
Question and response
Question
dig ch. NS
Answer
ch. 4 NS f.nic.ch.
ch. 4 NS e.nic.ch.
ch. 4 NS d.nic.ch.
ch. 4 NS b.nic.ch.
ch. 4 NS a.nic.ch.
Authority
The response has no authority records.
Additional
a.nic.ch. 172598 A 130.59.31.41
b.nic.ch. 172159 A 130.59.31.43
d.nic.ch. 172159 A 194.0.25.39
e.nic.ch. 172619 A 194.0.17.1
f.nic.ch. 21871 A 194.146.106.10
a.nic.ch. 172598 AAAA 2001:620:0:ff:0:0:0:56
b.nic.ch. 172159 AAAA 2001:620:0:ff:0:0:0:58
d.nic.ch. 172159 AAAA 2001:678:20:0:0:0:0:39
e.nic.ch. 172619 AAAA 2001:678:3:0:0:0:0:1
f.nic.ch. 21871 AAAA 2001:67c:1010:2:0:0:0:53
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0