$ionicModal don't recognize closeModal function after close app (run background) and open again

ionic-v1
1

Hello guys,
I have a modal in script:

  • html file

    <script id="computation.html" type="text/ng-template">
   <!-- some code in here -->
   <button class="selection-button " ng-click="closeModal('computation') ">CANCEL</button>
</script>
    • js file
$ionicModal.fromTemplateUrl('computation.html', function (modal) {
        $scope.computationModal = modal;
    }, {
        scope: $scope,
        animation: 'slide-in-up'
    });

   $scope.openModal = function (title) {
        if (title == SN_FOOTNOTES) {
          $scope.computationModal.show();       
        }
    };
    $scope.closeModal = function (title) {
        if (title == SN_FOOTNOTES) {
            $scope.computationModal.hide();
        }
    };

In app, I open model, then close app and open again, I cannot click CLOSE button :-?