diff --git a/src/Plugin/monitoring/SensorPlugin/ContentEntityAggregatorSensorPlugin.php b/src/Plugin/monitoring/SensorPlugin/ContentEntityAggregatorSensorPlugin.php
index a56b888..94dba93 100644
--- a/src/Plugin/monitoring/SensorPlugin/ContentEntityAggregatorSensorPlugin.php
+++ b/src/Plugin/monitoring/SensorPlugin/ContentEntityAggregatorSensorPlugin.php
@@ -201,9 +201,9 @@ class ContentEntityAggregatorSensorPlugin extends DatabaseAggregatorSensorPlugin
     // );
 
     // Load entities.
-    $entity_type = $this->getEntityTypeId();
+    $entity_type_id = $this->getEntityTypeId();
     $entities = $this->entityManager
-      ->getStorage($entity_type)
+      ->getStorage($entity_type_id)
       ->loadMultiple($entity_ids);
 
     // Get the fields to display from the settings.
@@ -211,6 +211,7 @@ class ContentEntityAggregatorSensorPlugin extends DatabaseAggregatorSensorPlugin
 
     // Render entities.
     $rows = [];
+    /* @var \Drupal\Core\Entity\FieldableEntityInterface $entity */
     foreach ($entities as $id => $entity) {
       $row = [];
       foreach ($fields as $field) {
@@ -242,9 +243,14 @@ class ContentEntityAggregatorSensorPlugin extends DatabaseAggregatorSensorPlugin
             break;
 
           default:
-            $property = $entity->getFieldDefinition($field)->getFieldStorageDefinition()->getMainPropertyName();
-            $value = $entity->$field->view(['label' => 'hidden']);
-            $row[] = $value ? \Drupal::service('renderer')->renderPlain($value) : $entity->$field->$property;
+            if ($entity->hasField($field)) {
+              $property = $entity->getFieldDefinition($field)->getFieldStorageDefinition()->getMainPropertyName();
+              $value = $entity->$field->view(['label' => 'hidden']);
+              $row[] = $value ? \Drupal::service('renderer')->renderPlain($value) : $entity->$field->$property;
+            }
+            else {
+              $row[] = t('invalid field');
+            }
             break;
         }
       }
@@ -255,7 +261,7 @@ class ContentEntityAggregatorSensorPlugin extends DatabaseAggregatorSensorPlugin
       );
     }
     if (count($rows) > 0) {
-      $header = $this->sensorConfig->getSetting('verbose_fields');
+      $header = $this->sensorConfig->getSetting('verbose_fields', ['ID, Label']);
       $output['entities'] = array(
         '#type' => 'table',
         '#header' => $header,
@@ -416,7 +422,7 @@ class ContentEntityAggregatorSensorPlugin extends DatabaseAggregatorSensorPlugin
     );
     $entity_type = $this->entityManager->getDefinition($this->getEntityTypeId());
     $form['verbose_fields']['available_fields'] = [
-    '#markup' => t('Available Fields for entity %type: <b>%fields</b>', [
+      '#markup' => t('Available Fields for entity %type: <b>%fields</b>', [
         '%type' => $entity_type->getLabel(),
         '%fields' => implode(', ', array_keys($this->entityManager->getBaseFieldDefinitions($this->getEntityTypeId())))
         ]