Apex domains cannot have CNAME records.
Question and response
Question
dig bbm-dns.com. NS
Answer
bbm-dns.com. 2 NS ns3.bbm-dns.com.
bbm-dns.com. 2 NS ns1.bbm-dns.com.
bbm-dns.com. 2 NS ns2.bbm-dns.com.
Authority
The response has no authority records.
Additional
ns1.bbm-dns.com. 2 A 95.217.34.10
ns2.bbm-dns.com. 2 A 95.217.34.54
ns3.bbm-dns.com. 2 A 135.181.237.61
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0