Fatal error: Uncaught TypeError: Frootbox\Db\Rows\NestedSet::getParent(): Return value must be of type Frootbox\Db\Rows\NestedSet, null returned in /var/www/marienschule/htdocs/lib/frootbox/db/src/Rows/NestedSet.php:182 Stack trace: #0 /var/www/marienschule/htdocs/lib/twig/twig/src/Extension/CoreExtension.php(1607): Frootbox\Db\Rows\NestedSet->getParent() #1 /var/www/marienschule/htdocs/files/cache/views/1f/1fc09686483f3d33b62eb5fadc5bd82489460ba74407d796b2d7fb9ba7027d7d.php(118): twig_get_attribute(Object(Twig\Environment), Object(Twig\Source), Object(Frootbox\Ext\Core\Images\Persistence\Category), 'getParent', Array, 'method', false, false, false, 56) #2 /var/www/marienschule/htdocs/lib/twig/twig/src/Template.php(394): __TwigTemplate_6c0e475d6f555824797c33193e422addee78550397e66df07146fff47a5cb1b2->doDisplay(Array, Array) #3 /var/www/marienschule/htdocs/lib/twig/twig/src/Template.php(367): Twig\Template->displayWithErrorHandling(Array, Array) #4 /var/www/marienschule/htdocs/lib/twig/twig/src/Template.php(379): Twig\Template->display(Array) #5 /var/www/marienschule/htdocs/lib/twig/twig/src/TemplateWrapper.php(40): Twig\Template->render(Array, Array) #6 /var/www/marienschule/htdocs/lib/twig/twig/src/Environment.php(277): Twig\TemplateWrapper->render(Array) #7 /var/www/marienschule/htdocs/cms/classes/View/Engines/Twig.php(206): Twig\Environment->render('/var/www/marien...', Array) #8 /var/www/marienschule/htdocs/cms/classes/Persistence/AbstractPlugin.php(545): Frootbox\View\Engines\Twig->render('/var/www/marien...', Array) #9 [internal function]: Frootbox\Persistence\AbstractPlugin->renderHtml(Object(Frootbox\Config\Config), Object(Frootbox\View\Engines\Twig), 'showCategory', Array) #10 /var/www/marienschule/htdocs/lib/php-di/invoker/src/Invoker.php(74): call_user_func_array(Array, Array) #11 /var/www/marienschule/htdocs/lib/php-di/php-di/src/Container.php(279): Invoker\Invoker->call(Array, Array) #12 /var/www/marienschule/htdocs/index.php(676): DI\Container->call(Array, Array) #13 {main} thrown in /var/www/marienschule/htdocs/lib/frootbox/db/src/Rows/NestedSet.php on line 182