Apex domains cannot have CNAME records.
Question and response
Question
dig 224-231.161.209.62.in-addr.arpa. NS
Answer
224-231.161.209.62.in-addr.arpa. 5 NS ns2.loxysoft.se.
224-231.161.209.62.in-addr.arpa. 5 NS ns1.loxysoft.se.
Authority
The response has no authority records.
Additional
ns1.loxysoft.se. 5 A 62.209.168.6
ns2.loxysoft.se. 5 A 213.132.109.39
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0