Wordpress Toolkit shows error: Cannot load the ionCube PHP Loader - it was already loaded

Symptoms

• Wordpress Toolkit shows most of the WordPress installations as damaged.
• While performing any actions the following error is shown:

  PLESK_ERROR: Cannot load the ionCube PHP Loader - it was already loaded\nFailed loading /usr/local/ioncube/ioncube_loader_lin_5.2.so: /usr/local/ioncube/ioncube_loader_lin_5.2.so: undefined symbol: zend_block_interruptions\nFailed loading /opt/plesk/php/7.1/lib/php/modules/ioncube_loader_lin_7.0.so: /opt/plesk/php/7.1/lib/php/modules/ioncube_loader_lin_7.0.so: cannot open shared object file: No such file or directory\"

• WordPress installation is finished with the errors but the instance can work properly:

  PLESK_WARN: WordPress was installed with errors:
  An error occurred while checking the administrator username on the WordPress instance 'example.com (My CMS)'.
  An error occurred while checking security keys of the WordPress installation 'example.com (My CMS)'.
  An error occurred while checking the status of pingbacks for the WordPress installation 'plesktest.ltd (My CMS)'. An error occurred while checking the status of scripts concatenation for WP admin panel on 'example.com (My CMS)'.

Cause

The problem occurred since ioncube loader was added twice in the PHP configuration.

Resolution

1. Connect to the server using SSH .
2. Use the following command to find all duplicate entries (example for PHP 7.0):

   # grep -Ri ioncube /opt/plesk/php/7.0/ 2>/dev/null
   /opt/plesk/php/7.0/etc/php.ini:zend_extension=ioncube_loader_lin_7.0.so
   /opt/plesk/php/7.0/etc/php.d/00-ioncube-loader.ini:zend_extension=ioncube_loader_lin_7.0.so

3. Comment one of the duplicate entry:
   

   # vi /opt/plesk/php/7.0/etc/php.ini
   # grep zend_extension /opt/plesk/php/7.0/etc/php.ini
   ; zend_extension=ioncube_loader_lin_7.0.so

4. Reread the PHP handlers settings:

   # plesk bin php_handler --reread