Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, class "\MailerLiteForms\Modules\Form" not found in /var/www/html/wp-includes/class-wp-hook.php:341 Stack trace: #0 /var/www/html/wp-includes/class-wp-hook.php(365): WP_Hook->apply_filters(NULL, Array) #1 /var/www/html/wp-includes/plugin.php(522): WP_Hook->do_action(Array) #2 /var/www/html/wp-settings.php(771): do_action('init') #3 /var/www/html/wp-config.php(140): require_once('/var/www/html/w...') #4 /var/www/html/wp-load.php(50): require_once('/var/www/html/w...') #5 /var/www/html/wp-blog-header.php(13): require_once('/var/www/html/w...') #6 /var/www/html/index.php(17): require('/var/www/html/w...') #7 {main} thrown in /var/www/html/wp-includes/class-wp-hook.php on line 341