diff --git a/src/ConditionalFieldsFormHelper.php b/src/ConditionalFieldsFormHelper.php
index 2a7d082ffc416a4dbab7a73b7d80e70ab9eb6e75..7940dec42fabcde68e412c1e1c81fa40fda12830 100644
--- a/src/ConditionalFieldsFormHelper.php
+++ b/src/ConditionalFieldsFormHelper.php
@@ -615,7 +615,8 @@ class ConditionalFieldsFormHelper {
                 }
 
                 if ($element_to_set_error['#access'] ?? TRUE) {
-                  if ($element_to_set_error['#type'] == 'hidden') {
+                  $type = $element_to_set_error['#type'] ?? '';
+                  if ($type == 'hidden') {
                     $element_to_set_error = NestedArray::getValue($form, array_slice($element_to_set_error['#array_parents'], 0, -1));
                     $title = $element_to_set_error['#title'];
                   }