Apex domains cannot have CNAME records.
Question and response
Question
dig as1836.ch. NS
Answer
as1836.ch. 1 NS ns01.agrinet.ch.
as1836.ch. 1 NS ns01.as1836.net.
as1836.ch. 1 NS ns01.as1836.ch.
Authority
The response has no authority records.
Additional
ns01.as1836.ch. 1 A 194.191.22.252
ns01.as1836.net. 1 A 194.191.23.252
ns01.agrinet.ch. 1 A 194.191.21.252
ns01.as1836.ch. 1 AAAA 2a01:2a8:2000:9:0:0:0:252
ns01.as1836.net. 1 AAAA 2a01:2a8:2000:a:0:0:0:252
ns01.agrinet.ch. 1 AAAA 2a01:2a8:2000:8:0:0:0:252
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0