Laravel won't return "failed" session on mail send

As first, that contact form works. When all data are valid, it works properly. 'success' session message works as well.

But, if I miss some of required data. Nothing is happend. On click on submit, page is reloaded, email isn't send (expected), but from some reason laravel don't return 'failed' session message.

Form

    <div class="row">
    <div class="col-12">
        <form action="" method="POST">
        
            <div class="row">
                <div class="form-group col-md-6">
                    <input class="form-control" name="name" id="name" placeholder="Ime i prezime *">
                </div>
                <div class="form-group col-md-6">
                    <input class="form-control" name="email" id="email" placeholder="Email *">
                </div>
                <div class="form-group col-md-6">
                    <input class="form-control" name="telephone" id="telephone" placeholder="Broj telefona">
                </div>
                <div class="form-group col-md-6">
                    <input class="form-control" name="website" id="website" placeholder="Adresa Web stranice">
                </div>
                <div class="form-group col-md-12">
                    <input class="form-control" name="subject" id="subject" placeholder="Naslov poruke">
                </div>
                <div class="form-group col-md-12">
                    <textarea class="form-control" rows="6" name="message" id="message" placeholder="Tekst poruke"></textarea>
                </div>
                <div class="col-md-12">
                    <button type="submit" class="btn btn-default submit btn-block"><i class="fa fa-paper-plane" aria-hidden="true"></i>Pošalji mail</button>
                </div>
            </div>
        </form>
    </div>
    @if (Session::has('success') || Session::has('failed'))
      <div class="col-12">
        @include('partials/_messages')
      </div>
    @endif
</div>

Partials (messages)

@if (Session::has('success'))

    <div class="alert alert-success" role="alert">
        <strong>Bravo:</strong> {!! Session::get('success') !!}
    </div>

@endif

@if (Session::has('failed'))

    <div class="alert alert-danger" role="alert">
        <strong>Pozor:</strong> {!! Session::get('failed') !!}
    </div>

@endif

@if (count($errors) > 0)

    <div class="alert alert-danger" role="alert">
        <strong>Pogreška:</strong>
        <ul>
        @foreach ($errors->all() as $error)

            <li></li>

        @endforeach
        </ul>
    </div>

@endif

Controller

public function postContact(Request $request) {
    $this->validate($request, array(
        'name' => 'required|max:50',
        'email' => 'required|email',
        'telephone' => 'max:50',
        'website' => 'max:50',
        'subject' => 'min:3',
        'message' => 'required|min:5'
    ));

    $data = array(
        'name' => $request->name,
        'email' => $request->email,
        'telephone' => $request->telephone,
        'website' => $request->website,
        'subject' => $request->subject,
        'bodyMessage' => $request->message
    );

    Mail::send('emails/contact', $data, function($message) use ($data){
        $message->from($data['email']);
        $message->to('no-replay@mail.eu');
        $message->subject($data['subject']);
    });

    Session::flash('success', 'Poruka je uspješno poslana!');

    return redirect()->route('website.index');
}

via Chebli Mohamed