dns1.convio.net has no CNAME records.
Question and response
Question
dig dns1.convio.net. NS
Answer
The response has no answer records.
Authority
convio.net. 1941 SOA dns1.convio.net. netadmin.convio.com. 2026022701 1800 300 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0