Apex domains cannot have CNAME records.
Question and response
Question
dig static.m1net.com.sg. NS
Answer
static.m1net.com.sg. 5 NS pridns.m1net.com.sg.
static.m1net.com.sg. 5 NS secdns.m1net.com.sg.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0