Ojs continuous loading problem

ojs I experienced problems when opening the administrator, loading continuously also on every journal when uploading downloading pdf I had problems, things kept happening because of what, does anyone have the same problem?

An unexpected error has occurred. Please reload the page and try again.

Every time you enter the journal a popup like that will appear

Hi @Dennis_Saputra,

For errors such as these, it is best to check your PHP error log and report on errors found there. Also, please indicate your specific OJS version (e.g. 3.3.0-13), as this is relevant for others who may assist you here on the forum to troubleshoot the issue.

Best regards,

PKP Team

thrown in /www/wwwroot/jurnal.ummi.ac.id/lib/pkp/lib/vendor/slim/slim/Slim/App.php on line 621" while reading response header from upstream, client:, server: jurnal.ummi.ac.id, request: “GET /index.php/japp/api/v1/submissions?status%5B%5D=4&status%5B%5D=3&status%5B%5D=5&searchPhrase=&count=20&offset=0&=1716363053084 HTTP/1.1”, upstream: “fastcgi://unix:/tmp/php-cgi-72.sock:”, host: “jurnal.ummi.ac.id”, referrer: “https://jurnal.ummi.ac.id/index.php/japp/submissions
2024/05/22 14:30:58 [error] 830#0: *3271 FastCGI sent in stderr: "PHP message: PHP Fatal error: Uncaught RuntimeException: Unexpected data in output buffer. Maybe you have characters before an opening <?php tag? in /www/wwwroot/jurnal.ummi.ac.id/lib/pkp/lib/vendor/slim/slim/Slim/App.php:621
Stack trace:
#0 /www/wwwroot/jurnal.ummi.ac.id/lib/pkp/lib/vendor/slim/slim/Slim/App.php(317): Slim\App->finalize(Object(APIResponse))
#1 /www/wwwroot/jurnal.ummi.ac.id/lib/pkp/classes/core/APIRouter.inc.php(115): Slim\App->run()
#2 /www/wwwroot/jurnal.ummi.ac.id/lib/pkp/classes/core/Dispatcher.inc.php(143): APIRouter->route(Object(Request))
#3 /www/wwwroot/jurnal.ummi.ac.id/lib/pkp/classes/core/PKPApplication.inc.php(281): Dispatcher->dispatch(Object(Request))
#4 /www/wwwroot/jurnal.ummi.ac.id/index.php(71): PKPApplication->execute()
#5 {main}

Current version: