我正在从 Laravel 5.2升级到5.3，也许这就是我得到这个错误的原因。但是请注意，这并不是在升级之后马上发生的。在访问应用程序中的一个链接后，这种情况突然发生了。点击这个链接(这是一个指向内部页面的链接)后，这个应用程序会将我登出，每当我试图登录时，我都会在 / home 页面上看到这个错误。如果我试图访问其他页面，它会自动重定向到 / 登录页面。这就像登录一样有效，但在那之后我就被注销了。
这是Laravel.log中的错误，也许您可以看出比我更多的内容：
UnexpectedValueException: The Response content must be a string or object implementing __toString(), "object" given. in /Sites/project/vendor/symfony/http-foundation/Response.php:403
Stack trace:
#0 /Sites/project/vendor/laravel/framework/src/Illuminate/Http/Response.php(48): Symfony\Component\HttpFoundation\Response->setContent(Object(Illuminate\Routing\Redirector))
#1 /Sites/project/vendor/symfony/http-foundation/Response.php(201): Illuminate\Http\Response->setContent(Object(Illuminate\Routing\Redirector))
#2 /Sites/project/vendor/laravel/framework/src/Illuminate/Routing/Router.php(1028): Symfony\Component\HttpFoundation\Response->__construct(Object(Illuminate\Routing\Redirector))
#3 /Sites/project/vendor/laravel/framework/src/Illuminate/Routing/Router.php(653): Illuminate\Routing\Router->prepareResponse(Object(Illuminate\Http\Request), Object(Illuminate\Routing\Redirector))
#4 /Sites/project/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(53): Illuminate\Routing\Router->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#5 /Sites/project/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/VerifyCsrfToken.php(65): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#6 /Sites/project/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(137): Illuminate\Foundation\Http\Middleware\VerifyCsrfToken->handle(Object(Illuminate\Http\Request), Object(Closure))
#7 /Sites/project/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(33): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#8 /Sites/project/vendor/laravel/framework/src/Illuminate/Routing/Middleware/SubstituteBindings.php(41): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#9 /Sites/project/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(137): Illuminate\Routing\Middleware\SubstituteBindings->handle(Object(Illuminate\Http\Request), Object(Closure))
#10 /Sites/project/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(33): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#11 /Sites/project/vendor/laravel/framework/src/Illuminate/Auth/Middleware/Authenticate.php(43): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#12 /Sites/project/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(137): Illuminate\Auth\Middleware\Authenticate->handle(Object(Illuminate\Http\Request), Object(Closure))
#13 /Sites/project/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(33): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#14 /Sites/project/vendor/laravel/framework/src/Illuminate/View/Middleware/ShareErrorsFromSession.php(49): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#15 /Sites/project/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(137): Illuminate\View\Middleware\ShareErrorsFromSession->handle(Object(Illuminate\Http\Request), Object(Closure))
#16 /Sites/project/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(33): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#17 /Sites/project/vendor/laravel/framework/src/Illuminate/Session/Middleware/StartSession.php(64): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#18 /Sites/project/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(137): Illuminate\Session\Middleware\StartSession->handle(Object(Illuminate\Http\Request), Object(Closure))
#19 /Sites/project/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(33): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#20 /Sites/project/vendor/laravel/framework/src/Illuminate/Cookie/Middleware/AddQueuedCookiesToResponse.php(37): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#21 /Sites/project/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(137): Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse->handle(Object(Illuminate\Http\Request), Object(Closure))
#22 /Sites/project/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(33): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#23 /Sites/project/vendor/laravel/framework/src/Illuminate/Cookie/Middleware/EncryptCookies.php(59): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#24 /Sites/project/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(137): Illuminate\Cookie\Middleware\EncryptCookies->handle(Object(Illuminate\Http\Request), Object(Closure))
#25 /Sites/project/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(33): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#26 /Sites/project/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(104): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#27 /Sites/project/vendor/laravel/framework/src/Illuminate/Routing/Router.php(655): Illuminate\Pipeline\Pipeline->then(Object(Closure))
#28 /Sites/project/vendor/laravel/framework/src/Illuminate/Routing/Router.php(629): Illuminate\Routing\Router->runRouteWithinStack(Object(Illuminate\Routing\Route), Object(Illuminate\Http\Request))
#29 /Sites/project/vendor/laravel/framework/src/Illuminate/Routing/Router.php(607): Illuminate\Routing\Router->dispatchToRoute(Object(Illuminate\Http\Request))
#30 /Sites/project/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(268): Illuminate\Routing\Router->dispatch(Object(Illuminate\Http\Request))
#31 /Sites/project/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(53): Illuminate\Foundation\Http\Kernel->Illuminate\Foundation\Http\{closure}(Object(Illuminate\Http\Request))
#32 /Sites/project/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/CheckForMaintenanceMode.php(46): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#33 /Sites/project/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(137): Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode->handle(Object(Illuminate\Http\Request), Object(Closure))
#34 /Sites/project/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(33): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#35 /Sites/project/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(104): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#36 /Sites/project/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(150): Illuminate\Pipeline\Pipeline->then(Object(Closure))
#37 /Sites/project/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(117): Illuminate\Foundation\Http\Kernel->sendRequestThroughRouter(Object(Illuminate\Http\Request))
#38 /Sites/project/public/index.php(52): Illuminate\Foundation\Http\Kernel->handle(Object(Illuminate\Http\Request))
#39 {main}