Apex domains cannot have CNAME records.
Question and response
Question
dig jib.co.th. NS
Answer
jib.co.th. 5 NS rudy.ns.cloudflare.com.
jib.co.th. 5 NS pola.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0