Apex domains cannot have CNAME records.
Question and response
Question
dig manfred-bergmann.com. NS
Answer
manfred-bergmann.com. 3 NS ns1.manfred-bergmann.com.
manfred-bergmann.com. 3 NS ns2.manfred-bergmann.com.
Authority
The response has no authority records.
Additional
ns1.manfred-bergmann.com. 3 A 98.126.201.148
ns2.manfred-bergmann.com. 3 A 108.174.50.118
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0