Try using: cpsess5112381149/webmail/src/redirect.php
When I designed the plugin, I set it to recognize the domain automatically. You only need to set the part after the domain. The trailing “/” is already included by the plugin.
Please let me know if it works, otherwise I’m going to have to say that the plugin is not compatible with CPanel.
Unfortunately, I don’t have access to CPanel to test the plugin.