You do not have to customize these pages - the error page is always available, whether customized or not.
1- Click on the Error pages button on the home page.
2- Click on the button of the required error page, such as the 403 button.
3- Enter the HTML code for the error page. You can use the buttons at the top of the page to insert variables into the displayed code.
Example:
<h1>404 Not Found</h1> <p>The requested page, <!--#echo var="REQUEST_URL" --> ,is not available.</p>4- Click on the Save button.
