Apex domains cannot have CNAME records.
Question and response
Question
dig nebenverdienst-heimarbeit.com. NS
Answer
nebenverdienst-heimarbeit.com. 5 NS ns-159.awsdns-19.com.
nebenverdienst-heimarbeit.com. 5 NS ns-1310.awsdns-35.org.
nebenverdienst-heimarbeit.com. 5 NS ns-566.awsdns-06.net.
nebenverdienst-heimarbeit.com. 5 NS ns-451.awsdns-56.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0