Hello Joao Taveira,

Thank you for reporting the error when opening Users → Manage in the Joomla administrator on the live site.

We have investigated this on our side using a backup of your site. The same functionality works correctly in that environment, which confirms this is not caused by your website files, our custom work, or any third-party extensions (such as Helix Ultimate, SP Page Builder, or Akeeba Backup).

Cause

The error:

Call to undefined function Joomla\CMS\Form\dom_import_simplexml()

occurs because a standard PHP extension required by Joomla core is missing or disabled on the live server.

The function dom_import_simplexml() is part of PHP's DOM/XML support. Joomla's core Form library uses it when building administrator screens, including the Users list.

Important: This requirement comes from core Joomla itself, not from any extension we installed or configured.

What Needs to Be Done

Please contact your hosting provider and ask them to enable the PHP XML/DOM extensions for the PHP version your live site is using.

You can copy and paste the message below and send it directly to your hosting support team:

Request for Hosting Support

Our Joomla 5 site requires the standard PHP XML/DOM extensions. Please ensure the following are installed and enabled for the PHP version serving our website (web/PHP-FPM, not CLI only):

• dom (provides dom_import_simplexml())
• xml
• SimpleXML
• libxml

On many Linux servers these are provided by a package such as php-xml or php8.x-xml (matching our PHP version). After enabling, please restart PHP-FPM and/or the web server.

Reference: Joomla core uses these in libraries/src/Form/Form.php. The error appears when accessing Administrator → Users → Manage.

After the Change

Once your host has enabled these extensions, please try Users → Manage again. No changes to the website files or extensions should be needed.

If the issue persists after the host confirms the extensions are enabled, let us know and we will assist further.

Kind regards

Hi Atick, thanks for your reply.

We will do as you suggest, and will give you feedback soos as we can

Kind regards,