Apex domains cannot have CNAME records.
Question and response
Question
dig bad-elster.net. NS
Answer
bad-elster.net. 5 NS ns-1298.awsdns-34.org.
bad-elster.net. 5 NS ns-667.awsdns-19.net.
bad-elster.net. 5 NS ns-1920.awsdns-48.co.uk.
bad-elster.net. 5 NS ns-1674.awsdns-17.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0