Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($function) must be a valid callback, non-static method social_facebook_ftgssbfw::register() cannot be called statically in /var/www/web1795/html/frankys-fahrschule/wp-includes/class-wp-hook.php:303 Stack trace: #0 /var/www/web1795/html/frankys-fahrschule/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters('', Array) #1 /var/www/web1795/html/frankys-fahrschule/wp-includes/plugin.php(470): WP_Hook->do_action(Array) #2 /var/www/web1795/html/frankys-fahrschule/wp-includes/widgets.php(1809): do_action('widgets_init') #3 /var/www/web1795/html/frankys-fahrschule/wp-includes/class-wp-hook.php(303): wp_widgets_init('') #4 /var/www/web1795/html/frankys-fahrschule/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters(NULL, Array) #5 /var/www/web1795/html/frankys-fahrschule/wp-includes/plugin.php(470): WP_Hook->do_action(Array) #6 /var/www/web1795/html/frankys-fahrschule/wp-settings.php(578): do_action('init') #7 /var/www/web1795/html/frankys-fahrschule/wp-config.php(88): require_once('/var/www/web179...') #8 /var/www/web1795/html/frankys-fahrschule/wp-load.php(50): require_once('/var/www/web179...') #9 /var/www/web1795/html/frankys-fahrschule/wp-blog-header.php(13): require_once('/var/www/web179...') #10 /var/www/web1795/html/frankys-fahrschule/index.php(17): require('/var/www/web179...') #11 {main} thrown in /var/www/web1795/html/frankys-fahrschule/wp-includes/class-wp-hook.php on line 303