Apex domains cannot have CNAME records.
Question and response
Question
dig ewcsdns.ch. NS
Answer
ewcsdns.ch. 3 NS dns1.ewcsdns.ch.
ewcsdns.ch. 3 NS dns3.ewcsdns.ch.
ewcsdns.ch. 3 NS dns2.ewcsdns.ch.
Authority
The response has no authority records.
Additional
dns1.ewcsdns.ch. 3 A 217.20.193.2
dns2.ewcsdns.ch. 3 A 217.20.194.3
dns3.ewcsdns.ch. 3 A 217.20.195.4
dns3.ewcsdns.ch. 3 AAAA 2a01:4aa0:0:2:f816:3eff:feb4:719c
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0