I’ve just spent the last few hours troubleshooting why a Joomla 2.5 site I’m working on was redirecting to the home index.php page for bad URLs instead of loading my template’s custom error.php page. Instead of the 404 response code, it was returning a 303 response: 303 See other
From what I can tell, it was because in the Global Configuration settings, I had the site offline for testing. So apparently even if logged in as a user who can view the offline site, it still won’t load the error page until the site is back online. When I put it back online, the 404 response was loading as expected… now I know.