Apex domains cannot have CNAME records.
Question and response
Question
dig benefitfocus.com. NS
Answer
benefitfocus.com. 5 NS destiny.ns.cloudflare.com.
benefitfocus.com. 5 NS damiete.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0