Fatal error: Uncaught Error: Class "SimpleXMLElement" not found in /var/www/html/plugins/generic/citationStyleLanguage/lib/vendor/seboettg/citeproc-php/src/Locale/Locale.php:60 Stack trace: #0 /var/www/html/plugins/generic/citationStyleLanguage/lib/vendor/seboettg/citeproc-php/src/CiteProc.php(209): Seboettg\CiteProc\Locale\Locale->__construct() #1 /var/www/html/plugins/generic/citationStyleLanguage/lib/vendor/seboettg/citeproc-php/src/CiteProc.php(168): Seboettg\CiteProc\CiteProc->init() #2 /var/www/html/plugins/generic/citationStyleLanguage/CitationStyleLanguagePlugin.php(608): Seboettg\CiteProc\CiteProc->render() #3 /var/www/html/plugins/generic/citationStyleLanguage/CitationStyleLanguagePlugin.php(650): APP\plugins\generic\citationStyleLanguage\CitationStyleLanguagePlugin->getCitation() #4 /var/www/html/plugins/generic/citationStyleLanguage/pages/CitationStyleLanguageHandler.php(109): APP\plugins\generic\citationStyleLanguage\CitationStyleLanguagePlugin->downloadCitation() #5 [internal function]: APP\plugins\generic\citationStyleLanguage\pages\CitationStyleLanguageHandler->download() #6 /var/www/html/lib/pkp/classes/core/PKPRouter.php(334): call_user_func() #7 /var/www/html/lib/pkp/classes/core/PKPPageRouter.php(278): PKP\core\PKPRouter->_authorizeInitializeAndCallRequest() #8 /var/www/html/lib/pkp/classes/core/Dispatcher.php(165): PKP\core\PKPPageRouter->route() #9 /var/www/html/lib/pkp/classes/core/PKPApplication.php(395): PKP\core\Dispatcher->dispatch() #10 /var/www/html/index.php(21): PKP\core\PKPApplication->execute() #11 {main} thrown in /var/www/html/plugins/generic/citationStyleLanguage/lib/vendor/seboettg/citeproc-php/src/Locale/Locale.php on line 60