ns4.dnsserver8.com has no CNAME records.
Question and response
Question
dig ns4.dnsserver8.com. NS
Answer
The response has no answer records.
Authority
dnsserver8.com. 3103 SOA ns1.dnsserver8.com. info. 2000100101 10800 3600 3600000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0