can’t get access to admin dasheboard - development

can’t get access to admin dasheboard

in my laravel project, I specified 2 guards, 1 for users and 1 for admins.
everything was working properly and today I find out that I couldn’t log in to the admin page.
I don’t know what happened! I did not change anything!!

when I try to log in as an admin, the login page gets reloads again!

btw, for the case of users, everything works fine!

this is the code

Adminlogincontroller

<?php
namespace AppHttpControllersAdmin;
use AppHttpControllersController;
use IlluminateFoundationAuthAuthenticatesUsers;
use IlluminateHttpRequest;
use IlluminateSupportFacadesAuth;
use AppAdmin;

class  AdminLoginController extends Controller 
    {
         use AuthenticatesUsers;

    protected $redirectTo = '/admin';

   public function __construct()
    {
    $this->middleware(array('guest:admin','guest:web'))->except('logout');
   }


public function login(Request $request)
{
  // Validate the form data
  $this->validate($request, [
    'email'   => 'required|email',
    'password' => 'required|min:6'
  ]);

  // Attempt to log the user in
  if (Auth::guard('admin')->attempt(['email' => $request->email, 'password' => $request->password], $request->remember)) {
    // if successful, then redirect to their intended location
    return redirect()->intended(route('dashboard'));
  }

  // if unsuccessful, then redirect back to the login with the form data
  return redirect()->back()->withInput($request->only('email', 'remember'));
}

 public function logout(Request $request)
   {
   $this->guard('admin')->logout();

    $request->session()->invalidate();

    return redirect()->route('AdminLogin');
     }

  public function showLoginForm()
   {
    return view('Admin.admin-login');
   }

   protected function guard()
   {
    return Auth::guard('admin');
  }

   protected function attemptLogin(Request $request)
{
    return $this->guard()->attempt(
        $this->credentials($request), $request->filled('remember')
    );
}
}

blade page

 <form action="/admin/login" method="post">
             

            <div class="input-field col s12">
      <i class="material-icons prefix">email
      </i>
      <input id="icon_prefix" name="email" type="text" class="validate">
      <label for="icon_prefix" style="color:#fff;">E-Mail</label>
    </div>

           <div class="input-field col s12">
       <i class="material-icons prefix">lock</i>
      <input id="icon_prefix" name="password" type="password" 
      class="validate">
      <label for="icon_prefix" style="color:#fff;">Mot de passe</label>
    </div>
            <p>
    <input type="checkbox" class="filled-in" id="filled-in-box" />
    <label for="filled-in-box" >Se rappeler de moi?</label>

    <a href="" class="right"> Mot de passe oublié </a>
   </p>
               <div class="row">
              <div class="col s12">

             <input type="submit" class="btn hoverable purple white-text" style="margin-top:30px;" value="connexion">

</div></div>





         </form>

routes:php

    Route::post('/admin/login', 'AdminAdminLoginController@login');
Route::get('/admin/logout', 'AdminAdminLoginController@logout');

 Route::get('/admin', 'AdminAdminController@show')->name('dashboard')

from Laravel Questions and Answers https://laravelquestions.com/php/cant-get-access-to-admin-dasheboard/
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