FTP + Unable to locate WordPress content directory (wp-content)

• All files should be owned by the actual user’s account, not the user account used for the httpd process.
• Group ownership is irrelevant unless there are specific group requirements for the web-server process permissions checking. This is not usually the case.
• All directories should be 755 or 750.
• All files should be 644 or 640. Exception: wp-config.php should be 440 or 400 to prevent other users on the server from reading it.
• No directories should ever be given 777, even upload directories. Since the PHP process is running as the owner of the files, it gets the owners permissions and – – can write to even a 755 directory.

You can use

chown www-data:www-data  -R * 
find . -type d -exec chmod 755 {} \;  
find . -type f -exec chmod 644 {} \;

you can also trying the following

add_filter('filesystem_method', create_function('$a', 'return "direct";' ));
define( 'FS_CHMOD_DIR', 0751 );
define('WP_TEMP_DIR', ABSPATH . 'wp-content/tmp');

The tmp folder wasn’t having the permission and that caused the website plugins from updating.