Apex domains cannot have CNAME records.
Question and response
Question
dig datafoundry.com. NS
Answer
datafoundry.com. 3 NS ns2.switchnap.com.
datafoundry.com. 3 NS ns1.switchnap.com.
Authority
The response has no authority records.
Additional
ns1.switchnap.com. 3 A 66.209.64.20
ns2.switchnap.com. 3 A 66.209.64.21
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0