[OJS 3.1.2-1] HTTP Error 500 in Statistics after delete published submission

I got error when i clicked Statistics after i delete only one published submission. My PHP error log as you can see below :

[Tue Aug 13 09:20:53.707874 2019] [:error] [pid 460:tid 1688] [client ::1:51040] PHP Warning: assert(): assert(is_a($object, ‘Submission’)) failed in E:\1xampp\htdocs\jurnal.stmik.ac.id\lib\pkp\classes\services\PKPStatsService.inc.php on line 121, referer: http://localhost/jurnal.stmik.ac.id/index.php/mti/submissions
[Tue Aug 13 09:20:53.709888 2019] [:error] [pid 460:tid 1688] [client ::1:51040] PHP Fatal error: Uncaught Error: Call to a member function getContextId() on null in E:\1xampp\htdocs\jurnal.stmik.ac.id\lib\pkp\classes\services\PKPStatsService.inc.php:127\nStack trace:\n#0 E:\1xampp\htdocs\jurnal.stmik.ac.id\lib\pkp\classes\services\PKPStatsService.inc.php(160): PKP\Services\PKPStatsService->getProperties(NULL, Array, Array)\n#1 E:\1xampp\htdocs\jurnal.stmik.ac.id\lib\pkp\pages\stats\PKPStatsHandler.inc.php(98): PKP\Services\PKPStatsService->getSummaryProperties(NULL, Array)\n#2 E:\1xampp\htdocs\jurnal.stmik.ac.id\lib\pkp\classes\core\PKPRouter.inc.php(390): PKPStatsHandler->publishedSubmissions(Array, Object(Request))\n#3 E:\1xampp\htdocs\jurnal.stmik.ac.id\lib\pkp\classes\core\PKPPageRouter.inc.php(231): PKPRouter->_authorizeInitializeAndCallRequest(Array, Object(Request), Array, false)\n#4 E:\1xampp\htdocs\jurnal.stmik.ac.id\lib\pkp\classes\core\Dispatcher.inc.php(134): PKPPageRouter->route(Object(Request))\n#5 E:\1xampp\htdocs\jurnal.stmik.ac.id\l in E:\1xampp\htdocs\jurnal.stmik.ac.id\lib\pkp\classes\services\PKPStatsService.inc.php on line 127, referer: http://localhost/jurnal.stmik.ac.id/index.php/mti/submissions

Hi @mahesAGX,

Try making this change to your installation:

Let me know if that resolves the issue.

Regards,
Alec Smecher
Public Knowledge Project Team

Thank you Alec, it’s working now.