Apex domains cannot have CNAME records.
Question and response
Question
dig flametree.com. NS
Answer
flametree.com. 5 NS ns1.flametree.com.
flametree.com. 5 NS ns1.outserv.net.
Authority
The response has no authority records.
Additional
ns1.outserv.net. 5 A 50.116.20.252
ns1.flametree.com. 5 A 159.89.247.92
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0