Fatal error: Uncaught TypeError: Return value of NF_Admin_Metaboxes_Calculations::registerReactMetabox() must be an instance of void, none returned in /home/bosscafe/ftp/serwisekspresow/wp-content/plugins/ninja-forms/includes/Admin/Metaboxes/Calculations.php:37
Stack trace:
#0 /home/bosscafe/ftp/serwisekspresow/wp-content/plugins/ninja-forms/includes/Admin/Metaboxes/Calculations.php(7): NF_Admin_Metaboxes_Calculations->registerReactMetabox()
#1 /home/bosscafe/ftp/serwisekspresow/wp-content/plugins/ninja-forms/ninja-forms.php(367): NF_Admin_Metaboxes_Calculations->__construct()
#2 /home/bosscafe/ftp/serwisekspresow/wp-content/plugins/ninja-forms/ninja-forms.php(1152): Ninja_Forms::instance()
#3 /home/bosscafe/ftp/serwisekspresow/wp-content/plugins/ninja-forms/ninja-forms.php(1155): Ninja_Forms()
#4 /home/bosscafe/ftp/serwisekspresow/wp-settings.php(462): include_once('/home/bosscafe/...')
#5 /home/bosscafe/ftp/serwisekspresow/wp-config.php(89): require_once('/home/bosscafe/...')
#6 /home/bosscafe/ftp/serwisekspresow/wp-loa in /home/bosscafe/ftp/serwisekspresow/wp-content/plugins/ninja-forms/includes/Admin/Metaboxes/Calculations.php on line 37