Apex domains cannot have CNAME records.
Question and response
Question
dig leepfrog.com. NS
Answer
leepfrog.com. 2 NS ultrix.leepfrog.com.
leepfrog.com. 2 NS denali.leepfrog.com.
leepfrog.com. 2 NS mojave.leepfrog.com.
Authority
The response has no authority records.
Additional
denali.leepfrog.com. 2 A 12.2.169.23
mojave.leepfrog.com. 2 A 12.2.169.37
ultrix.leepfrog.com. 2 A 52.89.61.229
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0