Apex domains cannot have CNAME records.
Question and response
Question
dig f2lfertilizantes.com. NS
Answer
f2lfertilizantes.com. 5 NS ns-1422.awsdns-49.org.
f2lfertilizantes.com. 5 NS ns-1949.awsdns-51.co.uk.
f2lfertilizantes.com. 5 NS ns-131.awsdns-16.com.
f2lfertilizantes.com. 5 NS ns-1274.awsdns-31.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0