diff --git a/models/Customer.php b/models/Customer.php
index 8405b45..b088e4e 100755
--- a/models/Customer.php
+++ b/models/Customer.php
@@ -82,7 +82,11 @@
     
         public function setBirthDate($value)
         {
-            $this->birthday = strtotime($value);
+            if (strtotime($value) !== false){
+                 $this->birthday = strtotime($value);
+            }else{
+                $this->birthday = null;
+            }
         }
     
         /**
--
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