Apex domains cannot have CNAME records.
Question and response
Question
dig ecoweb.ch. NS
Answer
ecoweb.ch. 2 NS ns1.igaia.ch.
ecoweb.ch. 2 NS ns2.ecoweb.ch.
ecoweb.ch. 2 NS ns1.ecoweb.ch.
Authority
The response has no authority records.
Additional
ns1.ecoweb.ch. 2 A 194.182.164.99
ns2.ecoweb.ch. 2 A 185.19.29.61
ns1.ecoweb.ch. 2 AAAA 2a04:c44:e00:3eb:482:6cff:fe00:d47
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0