Apex domains cannot have CNAME records.
Question and response
Question
dig edelkey.net. NS
Answer
edelkey.net. 5 NS ns1.edelkey.net.
edelkey.net. 5 NS ns2.edelkey.net.
Authority
The response has no authority records.
Additional
ns1.edelkey.net. 5 A 213.138.147.136
ns2.edelkey.net. 5 A 213.138.147.137
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0