Apex domains cannot have CNAME records.
Question and response
Question
dig edgekey.net. NS
Answer
edgekey.net. 5 NS adns1.akam.net.
edgekey.net. 5 NS a16-65.akam.net.
edgekey.net. 5 NS a11-65.akam.net.
edgekey.net. 5 NS a3-65.akam.net.
edgekey.net. 5 NS a9-65.akam.net.
edgekey.net. 5 NS ns1-2.akam.net.
edgekey.net. 5 NS a13-65.akam.net.
edgekey.net. 5 NS a6-65.akam.net.
edgekey.net. 5 NS a5-65.akam.net.
edgekey.net. 5 NS a12-65.akam.net.
edgekey.net. 5 NS usw6.akam.net.
edgekey.net. 5 NS a28-65.akam.net.
edgekey.net. 5 NS a18-65.akam.net.
Authority
The response has no authority records.
Additional
a13-65.akam.net. 3 A 2.22.230.65
a13-65.akam.net. 3 AAAA 2600:1480:800:0:0:0:0:41
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0