Apex domains cannot have CNAME records.
Question and response
Question
dig msg.chrl.nc.charter.net. NS
Answer
msg.chrl.nc.charter.net. 5 NS ns1.charter.com.
msg.chrl.nc.charter.net. 5 NS ns4.charter.com.
msg.chrl.nc.charter.net. 5 NS ns3.charter.com.
msg.chrl.nc.charter.net. 5 NS ns2.charter.com.
Authority
The response has no authority records.
Additional
ns1.CHARTER.COM. 4 A 24.216.90.1
ns2.CHARTER.COM. 4 A 24.216.90.2
ns3.CHARTER.COM. 4 A 24.240.146.1
ns4.CHARTER.COM. 4 A 24.240.146.2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0