We encounter some problems with a 'new' Joomla! website. A customer has moved there website to our server with the error below. This error was also present on previous server.
We also can't get into administrator section.
Warning: Class '\Joomla\CMS\Input\Input' not found in httpdocs/libraries/loader.php on line 663 Error: Failed to start application: Class 'Joomla\CMS\Input\Input' not found