If this error causes your entire site to be unavailable, go to wp-admin > Plugins
and temporarily disable the WP Staging plugin until we fix the issue.
wp-content/plugins/wp-staging(-pro)
with FTP to disable the WP Staging plugin.#0 /homepages/33/d150163012/htdocs/clickandbuilds/loyal2loyal.co.uk/wp-includes/class-wp-widget-factory.php(62): WP_Widget->__construct() #1 /homepages/33/d150163012/htdocs/clickandbuilds/loyal2loyal.co.uk/wp-includes/widgets.php(115): WP_Widget_Factory->register() #2 /homepages/33/d150163012/htdocs/clickandbuilds/loyal2loyal.co.uk/wp-content/themes/zerif-lite-default/functions.php(546): register_widget() #3 /homepages/33/d150163012/htdocs/clickandbuilds/loyal2loyal.co.uk/wp-includes/class-wp-hook.php(308): zerif_register_widgets() #4 /homepages/33/d150163012/htdocs/clickandbuilds/loyal2loyal.co.uk/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters() #5 /homepages/33/d150163012/htdocs/clickandbuilds/loyal2loyal.co.uk/wp-includes/plugin.php(517): WP_Hook->do_action() #6 /homepages/33/d150163012/htdocs/clickandbuilds/loyal2loyal.co.uk/wp-includes/widgets.php(1854): do_action() #7 /homepages/33/d150163012/htdocs/clickandbuilds/loyal2loyal.co.uk/wp-includes/class-wp-hook.php(308): wp_widgets_init() #8 /homepages/33/d150163012/htdocs/clickandbuilds/loyal2loyal.co.uk/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters() #9 /homepages/33/d150163012/htdocs/clickandbuilds/loyal2loyal.co.uk/wp-includes/plugin.php(517): WP_Hook->do_action() #10 /homepages/33/d150163012/htdocs/clickandbuilds/loyal2loyal.co.uk/wp-settings.php(623): do_action() #11 /homepages/33/d150163012/htdocs/clickandbuilds/loyal2loyal.co.uk/wp-config.php(93): require_once('/homepages/33/d...') #12 /homepages/33/d150163012/htdocs/clickandbuilds/loyal2loyal.co.uk/wp-load.php(50): require_once('/homepages/33/d...') #13 /homepages/33/d150163012/htdocs/clickandbuilds/loyal2loyal.co.uk/wp-blog-header.php(13): require_once('/homepages/33/d...') #14 /homepages/33/d150163012/htdocs/clickandbuilds/loyal2loyal.co.uk/index.php(17): require('/homepages/33/d...') #15 {main}