Laravel Logout Dropdown Not Showing After Adding Bootstrap

After adding Bootstrap in my layout app.blade.php,the default logout dropdown option is not showing.I add the Bootstrap MaxCDN from here.How to fix it? my laravel version is 5.7.21 And my app.blade.php holds everything default,i just add Bootstrap MaxCDN in the head tag.

<!-- CSRF Token -->
<meta name="csrf-token" content="{{ csrf_token() }}">

<title>{{ config('app.name', 'Laravel') }}</title>
<!-- Scripts -->
<script src="{{ asset('js/app.js') }}" ></script>
<!-- Fonts -->
<link rel="dns-prefetch" target="_blank" rel="nofollow noreferrer" href="//fonts.gstatic.com">
<link target="_blank" rel="nofollow noreferrer" href="https://fonts.googleapis.com/css?family=Nunito" rel="stylesheet" type="text/css">
<!-- Styles -->
<link target="_blank" rel="nofollow noreferrer" href="{{ asset('css/app.css') }}" rel="stylesheet">


        <!-- Latest compiled and minified CSS -->
        <link rel="stylesheet" target="_blank" rel="nofollow noreferrer" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.2.1/css/bootstrap.min.css">

        <!-- jQuery library -->
        <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

        <!-- Popper JS -->
        <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.6/umd/popper.min.js"></script>

        <!-- Latest compiled JavaScript -->
        <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.2.1/js/bootstrap.min.js"></script>

you need to delete laravel's bootstrap links (app.css and app.js) from layout.blade