vns1.dagent.com has no CNAME records.
Question and response
Question
dig vns1.dagent.com. NS
Answer
The response has no answer records.
Authority
dagent.com. 101 SOA ns2.exsbs.net. hostmaster.digitalagent.net. 120 300 300 300 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0