diff --git a/app/Models/PatientModel.php b/app/Models/PatientModel.php
index d97eb0d..b661d6e 100644
--- a/app/Models/PatientModel.php
+++ b/app/Models/PatientModel.php
@@ -344,12 +344,17 @@ class PatientModel extends Model {
   }
 
   // Conversion Time to Format Y-m-d\TH:i:s\Z
-  private function formatedDate($dateString) {
-    // return $date->format('Y-m-d H:i');
-    $dt = new \DateTime($dateString, new \DateTimeZone("UTC"));
+  private function formattedDate(?string $dateString): ?string {
+    try {
+        if (empty($dateString)) {
+            return null;
+        }
 
-    // Format jadi ISO 8601 dengan 'Z'
-    return $dt->format('Y-m-d\TH:i:s\Z');
+        $dt = new \DateTime($dateString, new \DateTimeZone("UTC"));
+        return $dt->format('Y-m-d\TH:i:s\Z'); // ISO 8601 UTC
+    } catch (\Exception $e) {
+        return null; 
+    }
   }
 
   // Conversion Time to Format j M Y