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