dns01.catch.net.tw has no CNAME records.
Question and response
Question
dig dns01.catch.net.tw. NS
Answer
The response has no answer records.
Authority
catch.net.tw. 900 SOA dns01.catch.net.tw. root.catch.net.tw. 2008010836 10800 3600 2592000 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0