Apex domains cannot have CNAME records.
Question and response
Question
dig freecnacertificationtraining.com. NS
Answer
freecnacertificationtraining.com. 5 NS ns1.freecnacertificationtraining.com.
freecnacertificationtraining.com. 5 NS ns2.freecnacertificationtraining.com.
Authority
The response has no authority records.
Additional
ns1.freecnacertificationtraining.com. 5 A 95.211.180.239
ns2.freecnacertificationtraining.com. 5 A 23.231.64.41
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0