ns2.luadns.net has no CNAME records.
Question and response
Question
dig ns2.luadns.net. NS
Answer
The response has no answer records.
Authority
luadns.net. 3600 SOA ns1.luadns.net. hostmaster.luadns.com. 1772610617 1200 120 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0