Apex domains cannot have CNAME records.
Question and response
Question
dig geiger-online.ch. NS
Answer
geiger-online.ch. 5 NS ns2.geiger-online.ch.
geiger-online.ch. 5 NS ns1.geiger-online.ch.
Authority
The response has no authority records.
Additional
ns1.geiger-online.ch. 5 A 176.9.84.209
ns2.geiger-online.ch. 5 A 37.187.108.161
ns1.geiger-online.ch. 5 AAAA 2a01:4f8:151:22c4:1eaf:0:0:53
ns2.geiger-online.ch. 5 AAAA 2001:41d0:a:3ca1:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0