Apex domains cannot have CNAME records.
Question and response
Question
dig bitnames.com. NS
Answer
bitnames.com. 2 NS anyns.pch.net.
bitnames.com. 2 NS ns2.us.bitnames.com.
bitnames.com. 2 NS ns2.eu.bitnames.com.
bitnames.com. 2 NS c.ns.bitnames.com.
bitnames.com. 2 NS ns1.us.bitnames.com.
bitnames.com. 2 NS ns1.eu.bitnames.com.
Authority
The response has no authority records.
Additional
c.ns.bitnames.com. 2 A 68.183.187.150
ns1.eu.bitnames.com. 2 A 165.227.133.206
ns1.us.bitnames.com. 2 A 178.128.191.122
ns2.eu.bitnames.com. 2 A 188.166.56.96
ns2.us.bitnames.com. 2 A 107.170.182.174
anyns.pch.net. 2 A 204.61.216.4
c.ns.bitnames.com. 2 AAAA 2400:6180:0:d0:0:0:16e6:2001
ns1.eu.bitnames.com. 2 AAAA 2a03:b0c0:3:d0:0:0:c0:4001
ns1.us.bitnames.com. 2 AAAA 2604:a880:2:d0:0:0:1ce8:7001
ns2.eu.bitnames.com. 2 AAAA 2a03:b0c0:2:d0:0:0:20:1001
anyns.pch.net. 2 AAAA 2001:500:14:6004:ad:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0