ns4.hostvirtual.com has no CNAME records.
Question and response
Question
dig ns4.hostvirtual.com. NS
Answer
The response has no answer records.
Authority
hostvirtual.com. 1688 SOA brad.ns.cloudflare.com. dns.cloudflare.com. 2394526928 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0