You can use the .htaccess file to quickly set customized error pages for your website.
First, set the folder in which the .htaccess file will be created, using the .htaccess location form at the top of the page. A click in the form field will open a pop-up window, from where you can browse to the desired website folder.
Then, go to the custom error pages menu. In there, mark the Enable Custom Error Pages checkbox. In the forms below, enter the addresses (URLs) of the new error pages you wish to use.
Once you are done, scroll down to the bottom of the page and click the “Generate” button. The newly created .htaccess file will take effect in up to 15 minutes.