You are not authorised to view this resource, you need to login, seeing this statement does not necessarily mean there is a problem with your site. If your site has content that requires you to login to view the content or article it would be normal to see this message. Most Joomla users realize that they will see this message if they are trying to access registered content items.

However there may come a time when you are logged in or you are the administrator and you get the 'authorised to view' message.

I have received a few e-mails for help saying that there is a 'problem with my site '! Getting this message when you are already logged in, as a rule, just means there is no content at the URL or link you clicked. You may have moved the article or item(s). A common issue would be your SEF URL's changed or you need to do a page refresh. But first your have to purge your SEF Component.

For example, if you were viewing an RSS feed at your site and then you entered your back-office and unpublished the RSS feed, once you refresh the page or try visiting the same RSS feed you will get the message, 'you are not authorised to view this resource', simply because it is not at the URL anymore.

Updated July 2009

Other reason is the content has no main link in the Joomla system. I have noticed this after giving a customer their site. Everything worked fine but what happened was they un-published a link from the main menu that lead into a section or category. Without the link Joomla was not able to find the content item.