internal.servercentral.com has no CNAME records.
Question and response
Question
dig internal.servercentral.com. NS
Answer
The response has no answer records.
Authority
servercentral.com. 511 SOA ns1.servercentral.net. dns.servercentral.net. 2025110302 600 600 600 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0