renown.xo.com has no CNAME records.
Question and response
Question
dig renown.xo.com. NS
Answer
The response has no answer records.
Authority
xo.com. 300 SOA ns-twbg.verizonwireless.com. hostmaster.xo.com. 2013072091 10800 3600 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0