Apex domains cannot have CNAME records.
Question and response
Question
dig ewadmin.ch. NS
Answer
ewadmin.ch. 4 NS dns3.ewdns.ch.
ewadmin.ch. 4 NS dns2.ewdns.ch.
ewadmin.ch. 4 NS dns1.ewdns.ch.
Authority
The response has no authority records.
Additional
dns1.ewdns.ch. 4 A 217.71.87.114
dns2.ewdns.ch. 4 A 212.71.102.42
dns3.ewdns.ch. 4 A 144.76.154.48
dns1.ewdns.ch. 4 AAAA 2a00:fb01:100:48:217:71:87:114
dns2.ewdns.ch. 4 AAAA 2a00:fb01:101:3:212:71:102:42
dns3.ewdns.ch. 4 AAAA 2a01:4f8:200:2233:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0