Laravel 5.4 - Cookie Queue

I found that:

Cookie queuing is not enabled for api requests, this is the reason why it didn't work.

I had to add in the middleware section of the appropriate file:

protected $middleware = [
        \App\Http\Middleware\TrustProxies::class,
        \App\Http\Middleware\CheckForMaintenanceMode::class,
        \Illuminate\Foundation\Http\Middleware\ValidatePostSize::class,
        \App\Http\Middleware\TrimStrings::class,
        \Illuminate\Foundation\Http\Middleware\ConvertEmptyStringsToNull::class,

        //added below line at end of the array
        \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
    ];

Open file App/Http/Kernel.php add the line \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class, in protected $middleware array as displayed in above code snippet and test again it should work now.

In case anyone fond their way here by Google, one way for cookie inclusion to silently fail is if you're explicitly defining your domain variable in its creation, and forgot to remove the "http://" from the beginning of it first. That's not the case with OP, but it was what brought me here. ;)