I am trying to create a basic bootstrap navigation menu with a toggle button. When the screen size is reduced, the navigation links hide as they should but the toggle button does not display. Why is this happening? Can someone help me figure this out? Thanks!
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta charset="utf-8">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<title>Stack</title>
<style type="text/css">
#nav {
background-color: yellow;
}
</style>
</head>
<body class="sidebar-collapse">
<nav class="navbar navbar-expand-md navbar-primaryfixed-top" id="nav">
<div class="container-fluid">
<a class="navbar-brand" href="#">
Stackoverflow
</a>
<button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbar2SupportedContent" aria-controls="navbar2SupportedContent" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse text-center justify-content-end" id="navbar2SupportedContent">
<ul class="navbar-nav">
<li class="nav-item">
<a class="nav-link" href="#test">
asdd
</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#servicesarea">
dsdsas
</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#aboutme">
daasdsda
</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#getintouchdiv">
afdfdf
</a>
</li>
</ul>
<button class="btn navbar-btn ml-2 text-white btn-success">
Sign in
</button>
</div>
</div>
</nav>
</body>
</html>
External links will be appreciated too.