The submenus of my drop-down menu are not displayed on any browser

I develop my site in php with the Laravel framework. Below is the source code for my drop-down menu, however the submenus are not displayed on browsers. What can be the problem ?

<div class="btn-group">
        @guest
          <button type="button" class="btn btn-light dropdown-toggle" data-bs-toggle="dropdown" aria-expanded="false">
            My Account
          </button>
          <ul class="dropdown-menu">
            <li><a class="dropdown-item" href="{{route('login')}}">Login</a></li>
            <li><a class="dropdown-item" href="{{route('register')}}">Register</a></li>
          </ul>
        @endguest

        @auth
          <button type="button" class="btn btn-light dropdown-toggle" data-bs-toggle="dropdown" aria-expanded="false">
            {{Auth::user()->name}}
          </button>
          <ul class="dropdown-menu">
            <li><a class="dropdown-item" href="{{route('app_logout')}}">Logout</a></li>
          </ul>

        @endauth


      </div>

I tried with Firefox, Google Chrome and Microsoft Edge browsers and I still have nothing