Apex domains cannot have CNAME records.
Question and response
Question
dig rioaccess.com. NS
Answer
rioaccess.com. 5 NS NS2.SCNRESEARCH.COM.
rioaccess.com. 5 NS NS1.SCNRESEARCH.COM.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0