Drupal 8 form builder error webform custom module - drupal

Question

can anyone guide me , I'm continuously facing this error , webform custom module Drupal 8
InvalidArgumentException: The form argument sun_webforms_usage_settings_page_form is not a valid form. in Drupal\Core\Form\FormBuilder->getFormId() (line 197 of F:\wamp\www\neo9\web\core\lib\Drupal\Core\Form\FormBuilder.php).
function neo_webforms_usage_settings_page_form($form, \Drupal\Core\Form\FormStateInterface $form_state)
{
$form = array();
$form['neo_webforms_usage_inactivity_time'] = array(
'#title' => t('Inactivity Time (seconds)'),
'#type' => 'textfield',
'#default_value' => \Drupal::state()->get('neo_webforms_usage_inactivity_time', 86400),
);
$form['neo_webforms_usage_alert_email'] = array(
'#title' => t('Alert receiver email (one per line).'),
'#type' => 'textarea',
'#default_value' => \Drupal::state()->get('neo_webforms_usage_alert_email', ""),
);
return system_settings_form($form);
}
and Controller
public function neo_webforms_usage_settings_page() {
$header = [
'#type' => 'markup',
'#markup' => t('<h4>Webform Usage Settings</h4>'),
];
$form = \Drupal::formBuilder()->getForm('neo_webforms_usage_settings_page_form');
$page = [
'header' => $header,
'form' => $form,
];
return $page;
}
}
Please anyone help me with that?

Answer 1

As per the official documentation of the FormBuilder getForm function, the parameter of getForm should be the Class/Instance name of the Form.
Parameters
\Drupal\Core\Form\FormInterface|string $form_arg: The value must be one of the following: The name of a class that implements \Drupal\Core\Form\FormInterface.
An instance of a class that implements \Drupal\Core\Form\FormInterface.
Try passing something like this:
$form = \Drupal::formBuilder()->getForm('\Drupal\module_name\Form\FormClassName');