Apex domains cannot have CNAME records.
Question and response
Question
dig 63.50.host.secureserver.net. NS
Answer
63.50.host.secureserver.net. 5 NS ans02.domaincontrol.com.
63.50.host.secureserver.net. 5 NS ans01.domaincontrol.com.
Authority
The response has no authority records.
Additional
ans01.domaincontrol.com. 3 A 97.74.97.35
ans02.domaincontrol.com. 3 A 173.201.65.35
ans01.domaincontrol.com. 3 AAAA 2603:5:2111:0:0:0:0:23
ans02.domaincontrol.com. 3 AAAA 2603:5:2211:0:0:0:0:23
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0