Apex domains cannot have CNAME records.
Question and response
Question
dig szwudang.com. NS
Answer
szwudang.com. 4 NS ens11.bigwww.com.
szwudang.com. 4 NS ens12.bigwww.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0