Apex domains cannot have CNAME records.
Question and response
Question
dig itconsult-dns.biz. NS
Answer
itconsult-dns.biz. 5 NS c.itconsult-dns.je.
itconsult-dns.biz. 5 NS e.itconsult-dns.biz.
itconsult-dns.biz. 5 NS a.itconsult-dns.net.
itconsult-dns.biz. 5 NS b.itconsult-dns.org.
itconsult-dns.biz. 5 NS d.itconsult-dns.co.uk.
Authority
The response has no authority records.
Additional
a.itconsult-dns.net. 5 A 193.201.42.1
b.itconsult-dns.org. 5 A 192.174.68.100
e.itconsult-dns.biz. 5 A 199.254.171.1
b.itconsult-dns.org. 5 AAAA 2001:67c:1bc:0:0:0:0:100
e.itconsult-dns.biz. 5 AAAA 2620:171:806:0:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0