To be more specific :
PHP Fatal error: Uncaught Error: Call to undefined function is_user_logged_in() in somepath/content/plugins/tuxedo-big-file-uploads/tuxedo_big_file_uploads.php:841
Stack trace: 0 somepath/content/plugins/tuxedo-big-file-uploads/tuxedo_big_file_uploads.php(244): BigFileUploads->get_upload_limit() 1 somepath/wp-includes/class-wp-hook.php(326): BigFileUploads->filter_upload_size_limit(52428800) 2 somepath/wp-includes/plugin.php(205): WP_Hook->apply_filters(52428800, Array) 3 somepath/wp-includes/media.php(4028): apply_filters('upload_size_lim…', 52428800, 52428800, 52428800) 4 somepath/content/plugins/ws-form-pro/includes/class-ws-form-common.php(1564): wp_max_upload_size()
