An error page informs a visitor when there is a problem accessing your site. Each type of problem has its own code. For example, a visitor who enters a nonexistent URL will see a 404 error, while an unauthorized user trying to access a restricted area of your site will see a 401 error.
1. Click the Error Pages icon under Advanced.
There are several different error pages you can customize. In this tutorial, we’re going to customize the 404 error page.
2. Click the 404 link.
3. This is where you create your custom error page. You can include one or more tags to further customize the page. You can also use HTML tags in your page thus making it easy to mate the look of your error page to the rest of your website.
For example,
4. Click the Save button to continue.
5. Your custom 404 error page has been created!