Hello @rcgillis yes i add my doamin and my subdomain in allowed_hosts
But I get this other error repeated several times 
[20-Sep-2023 22:02:55 UTC] PHP Fatal error: Uncaught RuntimeException: Unexpected data in output buffer. Maybe you have characters before an opening <?php tag? in /home/u879676513/domains/uovl.uk/public_html/journal/lib/pkp/lib/vendor/slim/slim/Slim/App.php:621
Stack trace:
#0 /home/u879676513/domains/uovl.uk/public_html/journal/lib/pkp/lib/vendor/slim/slim/Slim/App.php(317): Slim\App->finalize(Object(APIResponse))
#1 /home/u879676513/domains/uovl.uk/public_html/journal/lib/pkp/classes/core/APIRouter.inc.php(115): Slim\App->run()
#2 /home/u879676513/domains/uovl.uk/public_html/journal/lib/pkp/classes/core/Dispatcher.inc.php(144): APIRouter->route(Object(Request))
#3 /home/u879676513/domains/uovl.uk/public_html/journal/lib/pkp/classes/core/PKPApplication.inc.php(362): Dispatcher->dispatch(Object(Request))
#4 /home/u879676513/domains/uovl.uk/public_html/journal/index.php(68): PKPApplication->execute()
#5 {main}
thrown in /home/u879676513/domains/uovl.uk/public_html/journal/lib/pkp/lib/vendor/slim/slim/Slim/App.php on line 621