Apex domains cannot have CNAME records.
Question and response
Question
dig syncmail.net. NS
Answer
syncmail.net. 4 NS dns102.register.com.
syncmail.net. 4 NS dns101.register.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0