Apex domains cannot have CNAME records.
Question and response
Question
dig bmwgroup.com. NS
Answer
bmwgroup.com. 5 NS ns2.m-online.net.
bmwgroup.com. 5 NS ns3.m-online.net.
bmwgroup.com. 5 NS ns4.m-online.net.
bmwgroup.com. 5 NS ns.bmw.de.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0