@asmecher I managed to get the error logs
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] Slim Application Error:, referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] Type: RuntimeException, referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] Code: 5, referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] Message: Malformed UTF-8 characters, possibly incorrectly encoded, referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] File: /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/Http/Response.php, referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] Line: 356, referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] Trace: #0 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/api/v1/_submissions/PKPBackendSubmissionsHandler.inc.php(166): Slim\\Http\\Response->withJson(Array), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #1 [internal function]: PKPBackendSubmissionsHandler->getMany(Object(Slim\\Http\\Request), Object(APIResponse), Array), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #2 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/Handlers/Strategies/RequestResponse.php(40): call_user_func(Array, Object(Slim\\Http\\Request), Object(APIResponse), Array), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #3 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/Route.php(281): Slim\\Handlers\\Strategies\\RequestResponse->__invoke(Array, Object(Slim\\Http\\Request), Object(APIResponse), Array), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #4 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(117): Slim\\Route->__invoke(Object(Slim\\Http\\Request), Object(APIResponse)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #5 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/Route.php(268): Slim\\Route->callMiddlewareStack(Object(Slim\\Http\\Request), Object(APIResponse)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #6 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/App.php(503): Slim\\Route->run(Object(Slim\\Http\\Request), Object(APIResponse)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #7 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/classes/security/authorization/internal/ApiAuthorizationMiddleware.inc.php(77): Slim\\App->__invoke(Object(Slim\\Http\\Request), Object(APIResponse)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #8 [internal function]: ApiAuthorizationMiddleware->__invoke(Object(Slim\\Http\\Request), Object(APIResponse), Object(Slim\\App)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #9 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/DeferredCallable.php(57): call_user_func_array(Object(ApiAuthorizationMiddleware), Array), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #10 [internal function]: Slim\\DeferredCallable->__invoke(Object(Slim\\Http\\Request), Object(APIResponse), Object(Slim\\App)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #11 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(70): call_user_func(Object(Slim\\DeferredCallable), Object(Slim\\Http\\Request), Object(APIResponse), Object(Slim\\App)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #12 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/classes/security/authorization/internal/ApiCsrfMiddleware.inc.php(46): Slim\\App->Slim\\{closure}(Object(Slim\\Http\\Request), Object(APIResponse)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #13 [internal function]: ApiCsrfMiddleware->__invoke(Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #14 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/DeferredCallable.php(57): call_user_func_array(Object(ApiCsrfMiddleware), Array), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #15 [internal function]: Slim\\DeferredCallable->__invoke(Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #16 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(70): call_user_func(Object(Slim\\DeferredCallable), Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #17 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/classes/security/authorization/internal/ApiTokenDecodingMiddleware.inc.php(82): Slim\\App->Slim\\{closure}(Object(Slim\\Http\\Request), Object(APIResponse)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #18 [internal function]: ApiTokenDecodingMiddleware->__invoke(Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #19 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/DeferredCallable.php(57): call_user_func_array(Object(ApiTokenDecodingMiddleware), Array), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #20 [internal function]: Slim\\DeferredCallable->__invoke(Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #21 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(70): call_user_func(Object(Slim\\DeferredCallable), Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #22 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/classes/handler/APIHandler.inc.php(68): Slim\\App->Slim\\{closure}(Object(Slim\\Http\\Request), Object(APIResponse)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #23 [internal function]: APIHandler->{closure}(Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #24 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/DeferredCallable.php(57): call_user_func_array(Object(Closure), Array), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #25 [internal function]: Slim\\DeferredCallable->__invoke(Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #26 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(70): call_user_func(Object(Slim\\DeferredCallable), Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #27 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/classes/handler/APIHandler.inc.php(127): Slim\\App->Slim\\{closure}(Object(Slim\\Http\\Request), Object(APIResponse)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #28 [internal function]: APIHandler->{closure}(Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #29 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/DeferredCallable.php(57): call_user_func_array(Object(Closure), Array), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #30 [internal function]: Slim\\DeferredCallable->__invoke(Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #31 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(70): call_user_func(Object(Slim\\DeferredCallable), Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #32 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/classes/handler/APIHandler.inc.php(132): Slim\\App->Slim\\{closure}(Object(Slim\\Http\\Request), Object(APIResponse)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #33 [internal function]: APIHandler->{closure}(Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #34 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/DeferredCallable.php(57): call_user_func_array(Object(Closure), Array), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #35 [internal function]: Slim\\DeferredCallable->__invoke(Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #36 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(70): call_user_func(Object(Slim\\DeferredCallable), Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #37 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(117): Slim\\App->Slim\\{closure}(Object(Slim\\Http\\Request), Object(APIResponse)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #38 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/App.php(392): Slim\\App->callMiddlewareStack(Object(Slim\\Http\\Request), Object(APIResponse)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #39 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/classes/handler/APIHandler.inc.php(124): Slim\\App->process(Object(Slim\\Http\\Request), Object(APIResponse)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #40 [internal function]: APIHandler->{closure}(Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #41 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/DeferredCallable.php(57): call_user_func_array(Object(Closure), Array), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #42 [internal function]: Slim\\DeferredCallable->__invoke(Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #43 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(70): call_user_func(Object(Slim\\DeferredCallable), Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #44 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/classes/handler/APIHandler.inc.php(132): Slim\\App->Slim\\{closure}(Object(Slim\\Http\\Request), Object(APIResponse)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #45 [internal function]: APIHandler->{closure}(Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #46 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/DeferredCallable.php(57): call_user_func_array(Object(Closure), Array), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #47 [internal function]: Slim\\DeferredCallable->__invoke(Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #48 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(70): call_user_func(Object(Slim\\DeferredCallable), Object(Slim\\Http\\Request), Object(APIResponse), Object(Closure)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #49 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(117): Slim\\App->Slim\\{closure}(Object(Slim\\Http\\Request), Object(APIResponse)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #50 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/App.php(392): Slim\\App->callMiddlewareStack(Object(Slim\\Http\\Request), Object(APIResponse)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #51 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/lib/vendor/slim/slim/Slim/App.php(297): Slim\\App->process(Object(Slim\\Http\\Request), Object(APIResponse)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #52 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/classes/core/APIRouter.inc.php(115): Slim\\App->run(), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #53 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/classes/core/Dispatcher.inc.php(143): APIRouter->route(Object(Request)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #54 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/lib/pkp/classes/core/PKPApplication.inc.php(279): Dispatcher->dispatch(Object(Request)), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #55 /var/www/vhosts/designforsocialchange.org/httpdocs/journal/index.php(68): PKPApplication->execute(), referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] #56 {main}, referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] View in rendered output by enabling the "displayErrorDetails" setting., referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions
[Thu Aug 27 11:59:57 2020] [error] [client 69.6.26.122] , referer: https://designforsocialchange.org/journal/index.php/DISCERN-J/submissions