Fatal error: Uncaught Error: Call to undefined method Elementor\Utils::is_ajax() in /customers/3/4/1/johannessiemann.be/httpd.www/wp-content/plugins/elementor-pro/modules/forms/classes/ajax-handler.php:33
Stack trace:
#0 /customers/3/4/1/johannessiemann.be/httpd.www/wp-content/plugins/elementor-pro/modules/forms/module.php(176): ElementorPro\Modules\Forms\Classes\Ajax_Handler::is_form_submitted()
#1 /customers/3/4/1/johannessiemann.be/httpd.www/wp-content/plugins/elementor/core/base/module.php(85): ElementorPro\Modules\Forms\Module->__construct()
#2 /customers/3/4/1/johannessiemann.be/httpd.www/wp-content/plugins/elementor-pro/includes/modules-manager.php(59): Elementor\Core\Base\Module::instance()
#3 /customers/3/4/1/johannessiemann.be/httpd.www/wp-content/plugins/elementor-pro/plugin.php(327): ElementorPro\Manager->__construct()
#4 /customers/3/4/1/johannessiemann.be/httpd.www/wp-includes/class-wp-hook.php(287): ElementorPro\Plugin->on_elementor_init('')
#5 /customers/3/4/1/johannessiemann.be/httpd.www/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters(NULL, Array)
#6 /customers/3/4/1/johannessiemann.be/httpd.www/wp-includes/plugin.php(478): WP_Hook->do_action(Array)
#7 /customers/3/4/1/johannessiemann.be/httpd.www/wp-content/plugins/elementor/includes/plugin.php(646): do_action('elementor/init')
#8 /customers/3/4/1/johannessiemann.be/httpd.www/wp-includes/class-wp-hook.php(287): Elementor\Plugin->init('')
#9 /customers/3/4/1/johannessiemann.be/httpd.www/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters(NULL, Array)
#10 /customers/3/4/1/johannessiemann.be/httpd.www/wp-includes/plugin.php(478): WP_Hook->do_action(Array)
#11 /customers/3/4/1/johannessiemann.be/httpd.www/wp-settings.php(540): do_action('init')
#12 /customers/3/4/1/johannessiemann.be/httpd.www/wp-config.php(96): require_once('/customers/3/4/...')
#13 /customers/3/4/1/johannessiemann.be/httpd.www/wp-load.php(37): require_once('/customers/3/4/...')
#14 /customers/3/4/1/johannessiemann.be/httpd.www/wp-blog-header.php(13): require_once('/customers/3/4/...')
#15 /customers/3/4/1/johannessiemann.be/httpd.www/index.php(17): require('/customers/3/4/...')
#16 {main}
  thrown in /customers/3/4/1/johannessiemann.be/httpd.www/wp-content/plugins/elementor-pro/modules/forms/classes/ajax-handler.php on line 33