Apex domains cannot have CNAME records.
Question and response
Question
dig 35.190.64.in-addr.arpa. NS
Answer
35.190.64.in-addr.arpa. 5 NS ns01.fusionconnect.net.
35.190.64.in-addr.arpa. 5 NS ns02.fusionconnect.net.
35.190.64.in-addr.arpa. 5 NS ns03.fusionconnect.net.
35.190.64.in-addr.arpa. 5 NS ns04.fusionconnect.net.
Authority
The response has no authority records.
Additional
ns01.fusionconnect.net. 5 A 216.86.60.11
ns02.fusionconnect.net. 5 A 69.60.195.10
ns03.fusionconnect.net. 5 A 216.86.60.12
ns04.fusionconnect.net. 5 A 69.60.195.11
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0