When adding a domain redirect to a cPanel account that holds both domains you are not able to use the "All Public Domains" option.

Use the following steps.

1. Log into cPanel
2. Domains > Redirects
3. Type: (Select which one you like to use)
4. http ://(www.): from the dropdown select the domain you would like to redirect FROM
5. redirects to: put in the domain you would like to redirect TO.
6. Click Add.

If you try and use the "All Public Domains" you will end up gettting an Error about a redirection loop.