ns4.charter.com has no MX records.
Question and response
Question
dig ns4.charter.com. MX
Answer
The response has no answer records.
Authority
charter.com. 3600 SOA ns1.charter.com. hostmaster.charter.com. 2026021626 43200 3600 2419200 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0