Apex domains cannot have CNAME records.
Question and response
Question
dig 0.82.7.211.in-addr.arpa. NS
Answer
0.82.7.211.in-addr.arpa. 5 NS ns003-vush7uoqsf76d0ja.v.d-53.net.
0.82.7.211.in-addr.arpa. 5 NS ns003-vush7uoqsf76d0ja.v.d-53.jp.
0.82.7.211.in-addr.arpa. 5 NS ns003-vush7uoqsf76d0ja.v.d-53.info.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0