Apex domains cannot have CNAME records.
Question and response
Question
dig bss.net. NS
Answer
bss.net. 1 NS docks11.rzone.de.
bss.net. 1 NS shades13.rzone.de.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0