Apex domains cannot have CNAME records.
Question and response
Question
dig server.net. NS
Answer
server.net. 5 NS ns1.servernet.net.
server.net. 5 NS ns2.servernet.net.
Authority
The response has no authority records.
Additional
ns1.servernet.net. 5 A 85.208.196.34
ns2.servernet.net. 5 A 193.160.30.34
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0