Apex domains cannot have CNAME records.
Question and response
Question
dig rotofile.com. NS
Answer
rotofile.com. 5 NS ns1.rotofile.com.
rotofile.com. 5 NS ns2.rotofile.com.
Authority
The response has no authority records.
Additional
ns1.rotofile.com. 5 A 104.206.1.174
ns2.rotofile.com. 5 A 37.187.137.20
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0