Apex domains cannot have CNAME records.
Question and response
Question
dig baomo.net.tw. NS
Answer
baomo.net.tw. 4 NS dns1.taiwanmobile.com.
baomo.net.tw. 4 NS dns2.taiwanmobile.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0