Trying to get property 'id' of non-object

(1/1) ErrorException

Trying to get property 'id' of non-object

in PostController.php line 55
at HandleExceptions->handleError()in PostController.php line 55
at PostController->category()in Controller.php line 54
at Controller->callAction()in ControllerDispatcher.php line 45
at ControllerDispatcher->dispatch()in Route.php line 219
at Route->runController()in Route.php line 176
at Route->run()in Router.php line 681
at Router->Illuminate\Routing\{closure}()in Pipeline.php line 130
at Pipeline->Illuminate\Pipeline\{closure}()in SubstituteBindings.php line 41
at SubstituteBindings->handle()in Pipeline.php line 171
at Pipeline->Illuminate\Pipeline\{closure}()in VerifyCsrfToken.php line 78
at VerifyCsrfToken->handle()in Pipeline.php line 171
at Pipeline->Illuminate\Pipeline\{closure}()in ShareErrorsFromSession.php line 49
at ShareErrorsFromSession->handle()in Pipeline.php line 171
at Pipeline->Illuminate\Pipeline\{closure}()in StartSession.php line 56
at StartSession->handle()in Pipeline.php line 171
at Pipeline->Illuminate\Pipeline\{closure}()in AddQueuedCookiesToResponse.php line 37
at AddQueuedCookiesToResponse->handle()in Pipeline.php line 171
at Pipeline->Illuminate\Pipeline\{closure}()in EncryptCookies.php line 67
at EncryptCookies->handle()in Pipeline.php line 171
at Pipeline->Illuminate\Pipeline\{closure}()in Pipeline.php line 105
at Pipeline->then()in Router.php line 683
at Router->runRouteWithinStack()in Router.php line 658
at Router->runRoute()in Router.php line 624
at Router->dispatchToRoute()in Router.php line 613
at Router->dispatch()in Kernel.php line 170
at Kernel->Illuminate\Foundation\Http\{closure}()in Pipeline.php line 130
at Pipeline->Illuminate\Pipeline\{closure}()in TransformsRequest.php line 21
at TransformsRequest->handle()in Pipeline.php line 171
at Pipeline->Illuminate\Pipeline\{closure}()in TransformsRequest.php line 21
at TransformsRequest->handle()in Pipeline.php line 171
at Pipeline->Illuminate\Pipeline\{closure}()in ValidatePostSize.php line 27
at ValidatePostSize->handle()in Pipeline.php line 171
at Pipeline->Illuminate\Pipeline\{closure}()in CheckForMaintenanceMode.php line 63
at CheckForMaintenanceMode->handle()in Pipeline.php line 171
at Pipeline->Illuminate\Pipeline\{closure}()in TrustProxies.php line 57
at TrustProxies->handle()in Pipeline.php line 171
at Pipeline->Illuminate\Pipeline\{closure}()in Pipeline.php line 105
at Pipeline->then()in Kernel.php line 145
at Kernel->sendRequestThroughRouter()in Kernel.php line 110
at Kernel->handle()in index.php line 55