Apex domains cannot have CNAME records.
Question and response
Question
dig tcsasp.ch. NS
Answer
tcsasp.ch. 3 NS dns3.ewdns.ch.
tcsasp.ch. 3 NS dns1.ewdns.ch.
tcsasp.ch. 3 NS dns2.ewdns.ch.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0