Warning: Undefined array key "HTTP_ACCEPT_LANGUAGE" in /opt/dbis-projekt/dbis_server/src/Action/Frontend/Admin/AdminBasePage.php on line 91
Fatal error: Uncaught TypeError: substr(): Argument #1 ($string) must be of type string, null given in /opt/dbis-projekt/dbis_server/src/Action/Frontend/Admin/AdminBasePage.php:91
Stack trace:
#0 /opt/dbis-projekt/dbis_server/src/Action/Frontend/Admin/AdminBasePage.php(91): substr()
#1 /opt/dbis-projekt/dbis_server/vendor/php-di/php-di/src/Definition/Resolver/ObjectCreator.php(143): App\Action\Frontend\Admin\AdminBasePage->__construct()
#2 /opt/dbis-projekt/dbis_server/vendor/php-di/php-di/src/Definition/Resolver/ObjectCreator.php(71): DI\Definition\Resolver\ObjectCreator->createInstance()
#3 /opt/dbis-projekt/dbis_server/vendor/php-di/php-di/src/Definition/Resolver/ResolverDispatcher.php(71): DI\Definition\Resolver\ObjectCreator->resolve()
#4 /opt/dbis-projekt/dbis_server/vendor/php-di/php-di/src/Container.php(390): DI\Definition\Resolver\ResolverDispatcher->resolve()
#5 /opt/dbis-projekt/dbis_server/vendor/php-di/php-di/src/Container.php(139): DI\Container->resolveDefinition()
#6 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/CallableResolver.php(129): DI\Container->get()
#7 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/CallableResolver.php(90): Slim\CallableResolver->resolveSlimNotation()
#8 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/CallableResolver.php(63): Slim\CallableResolver->resolveByPredicate()
#9 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/Routing/Route.php(340): Slim\CallableResolver->resolveRoute()
#10 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/MiddlewareDispatcher.php(65): Slim\Routing\Route->handle()
#11 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/MiddlewareDispatcher.php(65): Slim\MiddlewareDispatcher->handle()
#12 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/Routing/Route.php(315): Slim\MiddlewareDispatcher->handle()
#13 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/Routing/RouteRunner.php(68): Slim\Routing\Route->run()
#14 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/Middleware/BodyParsingMiddleware.php(64): Slim\Routing\RouteRunner->handle()
#15 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/MiddlewareDispatcher.php(121): Slim\Middleware\BodyParsingMiddleware->process()
#16 /opt/dbis-projekt/dbis_server/vendor/slim/twig-view/src/TwigMiddleware.php(115): Psr\Http\Server\RequestHandlerInterface@anonymous->handle()
#17 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/MiddlewareDispatcher.php(121): Slim\Views\TwigMiddleware->process()
#18 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/Middleware/RoutingMiddleware.php(45): Psr\Http\Server\RequestHandlerInterface@anonymous->handle()
#19 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/MiddlewareDispatcher.php(121): Slim\Middleware\RoutingMiddleware->process()
#20 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/Middleware/MethodOverrideMiddleware.php(41): Psr\Http\Server\RequestHandlerInterface@anonymous->handle()
#21 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/MiddlewareDispatcher.php(121): Slim\Middleware\MethodOverrideMiddleware->process()
#22 /opt/dbis-projekt/dbis_server/vendor/selective/basepath/src/BasePathMiddleware.php(52): Psr\Http\Server\RequestHandlerInterface@anonymous->handle()
#23 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/MiddlewareDispatcher.php(121): Selective\BasePath\BasePathMiddleware->process()
#24 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/MiddlewareDispatcher.php(65): Psr\Http\Server\RequestHandlerInterface@anonymous->handle()
#25 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/App.php(199): Slim\MiddlewareDispatcher->handle()
#26 /opt/dbis-projekt/dbis_server/vendor/slim/slim/Slim/App.php(183): Slim\App->handle()
#27 /opt/dbis-projekt/dbis_server/public/index.php(45): Slim\App->run()
#28 {main}
thrown in /opt/dbis-projekt/dbis_server/src/Action/Frontend/Admin/AdminBasePage.php on line 91