My React application is not displaying the items of the collapsed navbar when using the Bootstrap navbar for mobile responsiveness. Can anyone please suggest what might be wrong here?
<!-- Bootstrap 4.1.3 library -->
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>
<!-- Start of HTML code -->
<header id="header" className="fixed-top d-flex align-items-center header-transparent">
<div className="container d-flex align-items-center navbar navbar-expand-lg navbar-light navbar-inverse ">
<div className="logo mr-auto">
<h1 className="text-light heading"><a href="/"><span>Prep</span></a></h1>
</div>
<button className="navbar-toggler navbar-dark" type="button" data-toggle="collapse" data-target="#navbarmenu" aria-expanded="false" aria-label="Toggle navigation">
<span className="navbar-toggler-icon"></span>
</button>
<nav className="nav-menu d-none d-lg-block">
<div className="collapse navbar-collapse" id="navbarmenu">
<ul className="navbar-nav mr-auto">
<li className="nav-item"><a href="#about">About</a></li>
<li className="nav-item"><a href="#details">Features</a></li>
<li className="nav-item"><a href="#team">Team</a></li>
<li className="nav-item"><a href="#contact">Contact</a></li>
<li className="nav-item"><a href="#faq">FAQs</a></li>
<li className="nav-item">
<Link to="/signup">Register</Link>
</li>
</ul>
</div>
</nav>
</div>
</header>