dns.tbcnet.net.tw has no CNAME records.
Question and response
Question
dig dns.tbcnet.net.tw. NS
Answer
The response has no answer records.
Authority
tbcnet.net.tw. 5343 SOA dns.tbcnet.net.tw. headend.tbcnet.net.tw. 2222367926 10800 3600 604800 38400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0