When i tried add a domain into cpanel addon it shows

Error from park wrapper: Using nameservers with the following IPs: <ip>,<ip> Sorry, the domain is already pointed to an IP address that does not appear to use DNS servers
associated with this server. Please transfer the domain to this servers nameservers or have your administrator add one of its nameservers to /etc/ip.remotedns and make the proper A entries on that remote nameserver.

It's mean, My domain ex: testing.com is not using the cpanel/whm DNS or nameservers.
This can be solved by :

1. change a nameservers in your domain registrar to pointing it to your CPANEL/WHM DNS servers
2. tweak your WHM to support external nameservers.

Login into your WHM with root access.
Server Configuration > Tweak Settings

Within this page you get a lot of options, the one I had to enable (tick) was:

Allow Creation of Parked/Addon Domains that resolve to other servers (i.e. domain transfers) This can be a major security problem. If you must have it enabled, be sure to not allow users to park common internet domains.

Basically it allows cPanel to Add domains on to external nameservers.
After you have added your add on into your CPANEL.
You need to un tick the allow creation of parked/addon domains that resolve to other servers again.
this will prevent any major security problem.