diff --git a/src/Form/SettingsForm.php b/src/Form/SettingsForm.php
index 9aeadd0..449a9ff 100644
--- a/src/Form/SettingsForm.php
+++ b/src/Form/SettingsForm.php
@@ -77,16 +77,38 @@ class SettingsForm extends ConfigFormBase {
    * {@inheritdoc}
    */
   public function submitForm(array &$form, FormStateInterface $form_state) {
-    $types = array_keys(array_filter($form_state->getValue(['filters', 'types'])));
-    $statuses = array_keys(array_filter($form_state->getValue(['filters', 'statuses'])));
-    $forbidden = array_keys(array_filter($form_state->getValue(['filters', 'refine', 'forbidden'])));
-    $allowed = array_keys(array_filter($form_state->getValue(['filters', 'refine', 'allowed'])));
+
+    $types = [];
+    $filters_types = $form_state->getValue(['filters', 'types']);
+    if (isset($filters_types) && is_array($filters_types)) {
+      $types = array_keys(array_filter($form_state->getValue(['filters', 'types'])));
+    }
+
+    $statuses = [];
+    $filters_statuses = $form_state->getValue(['filters', 'statuses']);
+    if (isset($filters_statuses) && is_array($filters_statuses)) {
+      $statuses = array_keys(array_filter($form_state->getValue(['filters', 'statuses'])));
+    }
+
+    $forbidden = [];
+    $filters_refine_forbidden = $form_state->getValue(['filters', 'refine', 'forbidden']);
+    if (isset($filters_refine_forbidden) && is_array($filters_refine_forbidden)) {
+      $forbidden = array_keys(array_filter($form_state->getValue(['filters', 'refine', 'forbidden'])));
+    }
+
+    $allowed = [];
+    $filters_refine_allowed = $form_state->getValue(['filters', 'refine', 'allowed']);
+    if (isset($filters_refine_allowed) && is_array($filters_refine_allowed)) {
+      $allowed = array_keys(array_filter($form_state->getValue(['filters', 'refine', 'allowed'])));
+    }
+
     $this->config('cl_block.settings')
       ->set('types', $types)
       ->set('statuses', $statuses)
       ->set('forbidden', $forbidden)
       ->set('allowed', $allowed)
       ->save();
+
     // Refresh the list of blocks after saving settings.
     $manager = isset($this->blockManager) ? $this->blockManager : \Drupal::service('plugin.manager.block');
     $manager->clearCachedDefinitions();