auth2.dns.gxn.net has no CNAME records.
Question and response
Question
dig auth2.dns.gxn.net. NS
Answer
The response has no answer records.
Authority
dns.gxn.net. 10800 SOA auth1.dns.gxn.net. hostmaster.gxn.net. 2013060301 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0