Apex domains cannot have CNAME records.
Question and response
Question
dig lilium.net. NS
Answer
lilium.net. 5 NS ns-810.awsdns-37.net.
lilium.net. 5 NS ns-47.awsdns-05.com.
lilium.net. 5 NS ns-2015.awsdns-59.co.uk.
lilium.net. 5 NS ns-1203.awsdns-22.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0