Sorry i just replied in another topic with somebody facing i thought was the same issue but i was using 5.2 and not 5.1 This is what i wrote and i solved it for now!
I think i found the solution, and its stupid of me, but i needed to read a lot better. You have to wrap your routes around in the web middleware like this
Route::group(['middleware' => ['web']], function () {
//your routes here.
});
The web middleware is stated in the app/http/Kernel.php see this
protected $middlewareGroups = [
'web' => [
\App\Http\Middleware\EncryptCookies::class,
\Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
\Illuminate\Session\Middleware\StartSession::class,
\Illuminate\View\Middleware\ShareErrorsFromSession::class,
\App\Http\Middleware\VerifyCsrfToken::class,
],
'api' => [
'throttle:60,1',
],
];
you see that there is a line, which made things really clear for me
\Illuminate\Session\Middleware\StartSession::class,
Thats why it was not persisting. Good luck!