Apex domains cannot have CNAME records.
Question and response
Question
dig straubsteins.com. NS
Answer
straubsteins.com. 4 NS ns1.straubsteins.com.
straubsteins.com. 4 NS ns2.straubsteins.com.
Authority
The response has no authority records.
Additional
ns1.straubsteins.com. 4 A 43.255.240.27
ns2.straubsteins.com. 4 A 23.137.139.22
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0