While adding rDNS file in cpanel server I was getting below mentioned error
Sorry, the domain xx.xx.104.in-addr.arpa is owned by another user (nobody)
I have found that at one point in the past this domain was present on this server.
I have removed remnants of the domain from /var/cpanel/users/system and removed references to it from /etc/userdomains and /etc/remotedomains.
I then rebuilt the various caches:
I am now able to add zone file without any issues