Apex domains cannot have CNAME records.
Question and response
Question
dig 50.180.107.host.secureserver.net. NS
Answer
50.180.107.host.secureserver.net. 2 NS ans02.domaincontrol.com.
50.180.107.host.secureserver.net. 2 NS ans01.domaincontrol.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0