Missing required parameter for route with laravel

Missing required parameter for [Route: conversations.show] [URI: conversations{user}] [Missing parameter: user].

I dont know how to solve this problem bc its only when i sent a message when i get back i have no problems and the message is there.

ConversationsController.php

<?php

namespace AppHttpControllers;

use IlluminateHttpRequest;
use AppModelsUser;
use IlluminateSupportFacadesAuth;
use AppRepositoryConversationsRepository;
use IlluminateAuthAuthManager;
use vendorlaravelframeworksrcIlluminateDatabaseEloquentBuilder;

class ConversationsController extends Controller
{
    /**
     * @var ConversationRepository
     */
    private $r;

       /**
     * @var AuthManager
     */
    private $auth;

    public function __construct(ConversationsRepository $conversationRepository, AuthManager $auth){
        $this->r = $conversationRepository;
        $this->auth = $auth;
    }
    
    
    
    public function index (){
        return view('conversations/index', [
            'users' => $this->r->getConversations($this->auth->user()->id)
            ]);
    }

    public function show (User $user){
        return view('conversations/show', [
            'users' => $this->r->getConversations($this->auth->user()->id),
            'user' => $user,
            'messages' => $this->r->getMessagesFor($this->auth->user()->id, $user->id)->get()->reverse()
        ]);
    }
    public function store (User $user, Request $request){
       $this->r->createMessage(
        $request->get('content'),
        $this->auth->user()->id,
        $user->id
       );
       return redirect(route('conversations.show', ['id'=> $user->id]));
    }
    

}

ConversationsRepository.php

<?php
namespace AppRepository;

use AppModelsUser;
use AppModelsMessage;
use IlluminateDatabaseEloquentBuilder;
use CarbonCarbon;
class ConversationsRepository{

    /**
     * @var User
     */

     private $user;
      /**
     * @var Message
     */

     private $message;




    public function __construct(User $user, Message $message){
        $this->user =$user;
        $this->message =$message;
    }

    public function getConversations(int $userId){
       return $this->user->newQuery()
        ->select('name', 'id')
        ->where('id', '!=', $userId)
        ->get();
    }

    public function createMessage(string $content, int $from, int $to){
        return $this->message->newQuery()->create([
            'content' => $content,
            'seller_id' => $from,
            'buyer_id' => $to,
            'created_at' => Carbon::now()
        ]);
    }
    public function getMessagesFor(int $from, int $to): Builder{
    return $this->message->newQuery()
    ->whereRaw("((buyer_id = $from AND seller_id = $to) OR (buyer_id = $to AND seller_id = $from))")
    ->orderBy('created_at', 'DESC');
    }

}

show.blade.php

@extends('layouts.app')

@section('content')
<div class="container">
    <div class="row">
    @foreach($users as $user)
            <div class="list-group">
    <a class="list-group-item" href="{{ route('conversations.show', $user->id )}}">{{$user->name}}</a>
    @endforeach
            <div class="col-md-9">
                    <div class="card">
                        <div class="card-header">{{ $user->name }}
                            <div class="card-body conversations">
                                @foreach($messages as $message)
                                <div class="row">
                                    <div class="col-md-10 {{ $message->from->id !== $user->id ?'offset-md-2 text-right' : ''}}">
                                        <p>
                                            <strong>{{($message->from->id !== $user->id ? 'Moi' : $message->from->name) }}</strong><br>
                                            {{ $message->content }}
                                        </p>
                                    </div>
                                </div>
                                @endforeach
                            <form action="" method="post">
                            @csrf
                            <div class="from-group">
                                <textarea name="content" placeholder="Ecrivez votre message" class="form-control"></textarea>
                            </div>
                            <button class="btn btn-primary" type="submit">Envoyer</button>
                            </form>
                         </div>
                    </div>
            </div>
        </div>
    </div>
</div>
</div>
@endsection 

I try to have a page where you have yours conversations but when i sent message a error happen