Apex domains cannot have CNAME records.
Question and response
Question
dig edgedns.world. NS
Answer
edgedns.world. 5 NS ns2.edgedns.world.
edgedns.world. 5 NS ns1.edgedns.world.
Authority
The response has no authority records.
Additional
ns1.edgedns.world. 5 A 5.101.39.39
ns2.edgedns.world. 5 A 5.101.71.71
ns1.edgedns.world. 5 AAAA 2a13:1ec0:1010:0:0:0:0:1039
ns2.edgedns.world. 5 AAAA 2a13:1ec0:1000:0:0:0:0:1071
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0