Apex domains cannot have CNAME records.
Question and response
Question
dig keepit.com. NS
Answer
keepit.com. 5 NS pns44.cloudns.net.
keepit.com. 5 NS nsp.dnsnode.net.
keepit.com. 5 NS ns0.keepit.org.
keepit.com. 5 NS pns41.cloudns.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0