Apex domains cannot have CNAME records.
Question and response
Question
dig canon.com. NS
Answer
canon.com. 5 NS ns1.canon.net.
canon.com. 5 NS ns2.jp.canon.com.
canon.com. 5 NS ns1.jp.canon.com.
canon.com. 5 NS ns3.jp.canon.com.
canon.com. 5 NS ns2.canon.net.
Authority
The response has no authority records.
Additional
ns1.jp.canon.com. 5 A 208.94.148.13
ns2.jp.canon.com. 5 A 208.80.124.13
ns3.jp.canon.com. 5 A 208.80.126.13
ns1.jp.canon.com. 5 AAAA 2600:1800:5:0:0:0:0:1
ns2.jp.canon.com. 5 AAAA 2600:1801:6:0:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0