diff --git a/dvg_appointments.module b/dvg_appointments.module
index 24d6112..5558c49 100644
--- a/dvg_appointments.module
+++ b/dvg_appointments.module
@@ -15,6 +15,7 @@
 
 define('DVG_APPOINTMENTS_ERRORCODE_UNKNOWN', 1);
 define('DVG_APPOINTMENTS_ERRORCODE_DATE_TIME', 2);
+define('DVG_APPOINTMENTS_ERRORCODE_MESSAGE', 3);
 
 /**
  * Implements hook_menu().
@@ -1669,6 +1670,10 @@ function dvg_appointments_book_appointment(&$form, &$form_state) {
         $form_state['rebuild'] = TRUE;
         break;
 
+      case DVG_APPOINTMENTS_ERRORCODE_MESSAGE:
+        form_set_error('appointments', $e->getMessage());
+        break;
+
       default:
         form_set_error('appointments', t('An unknown error occurred while booking your appointment. Please try again later.'));
     }