Apex domains cannot have CNAME records.
Question and response
Question
dig ichinaforum.com. NS
Answer
ichinaforum.com. 1 NS ns-1393.awsdns-46.org.
ichinaforum.com. 1 NS ns-1490.awsdns-58.org.
ichinaforum.com. 1 NS ns-143.awsdns-17.com.
ichinaforum.com. 1 NS ns-326.awsdns-40.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0