Apex domains cannot have CNAME records.
Question and response
Question
dig suantispam.com. NS
Answer
suantispam.com. 5 NS ns3.interplanet.com.mx.
suantispam.com. 5 NS ns2.interplanet.com.mx.
suantispam.com. 5 NS ns1.interplanet.com.mx.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0