Apex domains cannot have CNAME records.
Question and response
Question
dig 32.184.213.in-addr.arpa. NS
Answer
32.184.213.in-addr.arpa. 5 NS ans2.aso.ee.
32.184.213.in-addr.arpa. 5 NS ans1.aso.ee.
Authority
The response has no authority records.
Additional
ans1.aso.ee. 5 A 195.80.103.202
ans2.aso.ee. 5 A 195.80.96.217
ans1.aso.ee. 5 AAAA 2a02:88:0:417:195:80:103:202
ans2.aso.ee. 5 AAAA 2a02:88:0:420:195:80:96:217
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0