ns1.charter.com has no CNAME records.
Question and response
Question
dig ns1.charter.com. NS
Answer
The response has no answer records.
Authority
charter.com. 110 SOA ns1.charter.com. hostmaster.charter.com. 2026021645 43200 3600 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0