Joomla 5 brings speed, modern architecture, and enhanced security — but like any powerful system, it's not immune to errors. Whether you're migrating from Joomla 3 or starting fresh, you might run into some common issues.
This post covers real-world Joomla 5 errors, why they happen, and most importantly — how to fix them.
⚠️ 1. White Screen of Death (Blank Page)
Symptom: You visit your site or admin panel and all you see is a blank white screen.
Cause: Usually caused by a PHP error, outdated extension, or server configuration issue.
Fix:
- Enable error reporting in configuration.php:
public $error_reporting = 'maximum';- Check the logs/error.php or your server’s error_log.
- Disable recently installed extensions via the database (#__extensions table).
- Ensure PHP version is compatible (Joomla 5 needs PHP 8.1+).
🔐 "0 Call to undefined method" Error After Extension Install
Symptom: Error like:
0 Call to undefined method Joomla\CMS\Document\HtmlDocument::addScriptDeclaration()Cause: The extension is not compatible with Joomla 5.
Fix:
- Uninstall or disable the extension.
- Check for an updated version from the developer.
- Use only extensions listed as Joomla 5 compatible.
❌ 3. "404 Component Not Found" After Migration or Fresh Install
Symptom: Pages or menu links return a 404 error.
Cause: Missing components or bad menu item configuration.
Fix:
- Go to Menus > Main Menu, check if each menu item points to a valid component.
- Rebuild menus and clear cache.
- Verify that the extension is properly installed.
🛑 4. “The most recent request was denied because it contained an invalid security token.”
Symptom: You're logged out or redirected when submitting a form.
Cause: CSRF protection failed, often due to session expiration or missing token.
Fix:
- Ensure session is active and browser has cookies enabled.
- Check your template overrides for missing form.token.
Example (in your form HTML): - phpecho HTMLHelper::_('form.token');
- CopyEdit
- Update any old extensions or templates that don’t use Joomla 5's token system.
🔁 5. SEO-Friendly URLs Not Working
Symptom: Links break or redirect incorrectly when SEF (Search Engine Friendly) URLs are enabled.
Fix:
- Rename htaccess.txt to .htaccess in your Joomla root directory.
- Enable Use URL Rewriting in Global Configuration.
- Ensure mod_rewrite is enabled on the server (Apache/Nginx).
🔒 6. Admin Login Doesn’t Work (After Migration)
Symptom: You’re locked out or credentials stop working after a Joomla upgrade.
Fix:
- Reset password via the database:
- sqlUPDATE `#__users` SET `password` = MD5('newpassword') WHERE `username` = 'admin';
- CopyEdit
- Clear cookies and browser cache.
- If 2FA is enabled and causing issues, disable the plugin in the #__extensions table.
⚙️ 7. Database Errors After Update
Symptom: Error like: Database schema version does not match CMS version.
Fix:
- Go to System > Maintenance > Database > Fix.
- Joomla will attempt to update or fix the database structure.
- Always back up your site before updates.
🧰 Final Tips
- Use Joomla’s built-in Debug Mode:
Enable it via System > Global Configuration > System > Debug System = Yes. - Always update extensions and templates to their latest Joomla 5 versions.
- Use tools like Akeeba Backup to protect your site before changes.
