Apex domains cannot have CNAME records.
Question and response
Question
dig twcnc.com. NS
Answer
twcnc.com. 5 NS ns1.twcable.com.
twcnc.com. 5 NS ns3.twcable.com.
twcnc.com. 5 NS ns2.twcable.com.
Authority
The response has no authority records.
Additional
ns1.twcable.com. 5 A 165.237.86.252
ns3.twcable.com. 5 A 67.48.224.74
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0