Setting up Custom Error Pages in cPanel
The most common website errors such as 404 Page Missing, 401 Access Denied, etc can be customized to your liking.
To customize them, log in to CPanel. Then click on the Custom Error Pages button:
From there, select the code number of the error you wish to customize.
The next page is the editing page, In the text box, you can edit the HTML code for the error page.