WP admin CP does not work properly after the website was migrated.
The domains error log throws the following error:
[Sat Mar 14 16:54:47 2015] [error] [client 203.0.113.2] PHP Fatal error: Access to undeclared static property: WP_Screen::$this in /var/www/vhosts/example.com/httpdocs/wp-admin/includes/screen.php on line 706
Unhandled parameter defined in the source code.
Backup the original file:
Open it on line 706 and replace:
<?php echo self::$this->_help_sidebar; ?>
<?php echo $this->_help_sidebar; ?>