diff --git a/CHANGELOG.md b/CHANGELOG.md
index bbaf66e..27ef556 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,8 @@ before starting to add changes. Use example [placed in the end of the page](#exa
 
 ## [Unreleased]
 
+- Fix bug in MitidChildrenSelectAjaxBehaviour.php [192](https://github.com/OS2Forms/os2forms/pull/192)
+
 ## [4.1.0] 2025-06-03
 
 - [PR-176](https://github.com/OS2Forms/os2forms/pull/176)
diff --git a/modules/os2forms_nemid/src/Element/MitidChildrenSelectAjaxBehaviour.php b/modules/os2forms_nemid/src/Element/MitidChildrenSelectAjaxBehaviour.php
index e88c218..c38f94c 100644
--- a/modules/os2forms_nemid/src/Element/MitidChildrenSelectAjaxBehaviour.php
+++ b/modules/os2forms_nemid/src/Element/MitidChildrenSelectAjaxBehaviour.php
@@ -45,6 +45,10 @@ public static function mitidChildrenSelectAjax(array &$form, FormStateInterface
     if ($cprPlugin->isReady()) {
       $cprLookupResult = $cprPlugin->lookup($childCpr);
 
+      if (!$cprLookupResult->isSuccessful()) {
+        return $response;
+      }
+
       /** @var \Drupal\webform\WebformSubmissionForm $webformSubmissionForm */
       $webformSubmissionForm = $form_state->getFormObject();
       /** @var \Drupal\webform\WebformSubmissionInterface $webformSubmission */