Apex domains cannot have CNAME records.
Question and response
Question
dig tillo.ch. NS
Answer
tillo.ch. 5 NS fat.tillo.ch.
tillo.ch. 5 NS ns2.afraid.org.
tillo.ch. 5 NS puck.nether.net.
Authority
The response has no authority records.
Additional
fat.tillo.ch. 5 A 31.3.135.237
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0