If you have uploaded content through Joomla! and cannot change file or folder permissions, this often happens when you do not have an FTP account configured in Joomla!
When uploading the website's files, the content manager uses the web server process instead of the FTP user's permissions to manage folders and files, causing the permissions to be configured incorrectly.
To avoid this problem, you need to configure an FTP account in Joomla! in the “Configuración” section of the content management system's administration interface.
If you have SSH access to your Cloud Server, you can fix this problem by reassigning the correct owner and group to folders that were configured with the owner and group “www-data“.