ns.premiumwebservers.com has no CNAME records.
Question and response
Question
dig ns.premiumwebservers.com. NS
Answer
The response has no answer records.
Authority
premiumwebservers.com. 3077 SOA nxg9180.premiumwebservers.com. hostmaster.premiumwebservers.com. 132 900 600 86400 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0