How do i fix this error i'm getting "Sorry, the page you are looking for could not be found."

I have this application where I am trying to get the the author of a question to be able to mark an answer as the best answer.

I have an AcceptAnswerController created which has been registered in the routes/web.php file as below:

AcceptAnswerController.php

class AcceptAnswerController extends Controller
{
    public function __invoke(Answer $answer) 
    {
        $this->authorize('accept', $answer);

        $answer->question->acceptBestAnswer($answer);
        return back();
    }
}

web.php

Route::get('/', function () {
    return view('welcome');
});

Auth::routes();

Route::get('/home', 'HomeController@index')->name('home');

Route::resource('questions', 'QuestionsController')->except('show');

Route::resource('questions.answers', 'AnswersController')->only(['store', 'edit', 'update', 'destroy']);

Route::get('questions/{slug}', 'QuestionsController@show')->name('questions.show');

Route::post('answers/{answer}/accept', 'AcceptAnswerController')->name('answers.accept');

In my Answers view, i have the following:

<div class="row mt-4">
    <div class="col-md-12">
        <div class="card">
            <div class="card-body">
                <div class="card-title">
                    <h2></h2>
                </div>
                <hr>
                @include ('layouts._messages')

                @foreach ($answers as $answer)
                    <div class="media">
                        <div class="d-fex flex-column vote-controls">
                            <a title="This answer is useful" class="vote-up">
                                <i class="fas fa-caret-up fa-3x"></i>
                            </a>
                            <span class="votes-count">1230</span>
                            <a title="This answer is not useful" class="vote-down off">
                                <i class="fas fa-caret-down fa-3x"></i>
                            </a>
                            @can ('accept', $answer)
                                <a title="Mark this answer as best answer" 
                                    class=" mt-2"
                                    onclick="event.preventDefault(); document.getElementById('answer-').submit();"
                                    >
                                    <i class="fas fa-check fa-2x"></i>                                    
                                </a>
                                <form id="answer-" action="" method="POST" style="display:none;">
                                    @csrf
                                </form>
                            @else
                                @if ($answer->is_best)
                                    <a title="The question owner accepted this answer as best answer" 
                                        class=" mt-2"                                        
                                        >
                                        <i class="fas fa-check fa-2x"></i>                                    
                                    </a>
                                @endif
                            @endcan
                        </div>
                        <div class="media-body">
                            {!! $answer->body_html !!}
                            <div class="row">
                                <div class="col-4">
                                    <div class="ml-auto">
                                        @can ('update', $answer)
                                            <a href="" class="btn btn-sm btn-outline-info">Edit</a>
                                        @endcan
                                        @can ('delete', $answer)
                                            <form class="form-delete" method="post" action="">
                                                @method('DELETE')
                                                @csrf
                                                <button type="submit" class="btn btn-sm btn-outline-danger" onclick="return confirm('Are you sure?')">Delete</button>
                                            </form>
                                        @endcan
                                    </div>
                                </div>
                                <div class="col-4"></div>
                                <div class="col-4">
                                    <span class="text-muted">Answered </span>
                                    <div class="media mt-2">
                                        <a href="" class="pr-2">
                                            <img src="">
                                        </a>
                                        <div class="media-body mt-1">
                                            <a href=""></a>
                                        </div>
                                    </div>
                                </div>
                            </div>                            
                        </div>
                    </div>
                    <hr>
                @endforeach
            </div>
        </div>
    </div>
</div>

Once the author of the question clicks on the check icon, it should mark the answer as the best answer but i get the following error:

Sorry, the page you are looking for could not be found

I see that the answer id is missing in the url as follows:

http://localhost:8000/answers//accept

when it should actually be something like this:

http://localhost:8000/answers/1/accept

I can't seem to figure out why as i passed it as a route parameter in the form action. Same thing happens if a user is trying to edit his answer.

via Chebli Mohamed