Apex domains cannot have CNAME records.
Question and response
Question
dig igaia.ch. NS
Answer
igaia.ch. 5 NS ns2.ecoweb.ch.
igaia.ch. 5 NS ns1.igaia.ch.
igaia.ch. 5 NS ns1.ecoweb.ch.
Authority
The response has no authority records.
Additional
ns1.igaia.ch. 5 A 159.69.1.15
ns1.igaia.ch. 1 AAAA 2a01:4f8:1c0c:52e0:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0