Apex domains cannot have CNAME records.
Question and response
Question
dig lstn.net. NS
Answer
lstn.net. 5 NS ns3.limestonenetworks.com.
lstn.net. 5 NS ns1.limestonenetworks.com.
lstn.net. 5 NS ns2.limestonenetworks.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0