Error pages display when unexpected problems occur whilst using the website, these can range from broken links & missing pages, to unauthorised access. The most common error, is the infamous 404 page, which displays when a page is missing.
It’s important you don’t forget to create error pages, there are a number of different errors and they may not all be applicable. Think outside the box, your error page can re-route traffic back into your site, use error pages as an opportunity to keep visitors browsing your website, they don’t just have to show text.
If your error page redirects aren’t already setup you may need to add some code to your .htaccess file. Here’s a quick example of how to assign a 404 redirect:
ErrorDocument 404 /404.shtml
For more information about the code behind error redirects visit http://httpd.apache.org/docs/2.0/mod/core.html#errordocument