Laravel Session Middleware broken

On my local system everything works fine, but after deploying Laravel 5.2 on our test system it looks like the session middleware is broken. Can someone help here?

Argument 1 passed to Illuminate\Session\Middleware\    
StartSession::addCookieToResponse() must be an instance of  
Symfony\Component\HttpFoundation\Response, boolean given, called in   
... /httpdocs/service/vendor/laravel/framework/src/Illuminate/Session 
/Middleware/StartSession.php on line 72 and defined

The global middlewares:

protected $middleware = [
    \Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode::class,
    \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
    \Illuminate\Session\Middleware\StartSession::class,
    \Illuminate\View\Middleware\ShareErrorsFromSession::class,
    \App\Http\Middleware\CORSMiddleware::class,
    \LucaDegasperi\OAuth2Server\Middleware\OAuthExceptionHandlerMiddleware::class
];