ns2.tw1.com has no CNAME records.
Question and response
Question
dig ns2.tw1.com. NS
Answer
The response has no answer records.
Authority
tw1.com. 9203 SOA ns1.tw1.com. root.ns1.tw1.com. 2025050522 3600 900 1209600 43200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0