Apex domains cannot have CNAME records.
Question and response
Question
dig wip.cimbbank.com.sg. NS
Answer
wip.cimbbank.com.sg. 5 NS KC2GTMINT002.CIMB.com.sg.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0