Last time I wrote a tutorial on How to create cpanel using WHM, though one thing happened with me while adding an addon domain to my cpanel account. And I’m sure this might happen to you , so this guide will help you to get rid of this issue.
The Error which I was getting was
Error from park wrapper: Using name servers with the following IPs
In short I was not allowed to add domains whose name servers resolve to other servers. To resolve this issue you need to configure this thing from your WHM, if you are getting this problem into your shared hosting cpanel, you need to ask your hosting provider to configure it for you.
Login to WHM and click on Server Configuration >Tweak Settings
In the options search for options which says (usually 3rd option)
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.
Put a check mark on it and click on save. This will let you add addon domains which resolve to other address. So now you can add domains which resolve to external name servers without any problem.
This guide will help you once you move to your own managed VPS or working on WHM.