be ensure you inserted libraries of bootsrap correctly and be sure nav content id equals to target

<link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-giJF6kkoqNQ00vy+HMDP7azOuL0xtbfIcaT9wjKHr8RbDVddVHyTfAAsrekwKmP1" crossorigin="anonymous">
    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.bundle.min.js" integrity="sha384-ygbV9kiqUc6oa4msXn9868pTtWMgiQaeYH7/t7LECLbyPA2x65Kgf80OJFdroafW" crossorigin="anonymous"></script>

<nav class="navbar navbar-expand-lg navbar-light bg-light"role="navigation">
     <a class="navbar-brand" href="#"role="navigation">Navbar</a>
    <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
<div class="collapse navbar-collapse" id="navbarSupportedContent">
<ul class="navbar-nav">
<li class="nav-item active">
  <a class="nav-link" href="index.html">Home <span class="sr-only">(current)</span></a>
  </li>
  <li class="nav-item dropdown">
         <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Links</a>
          <div class="dropdown-menu">
            <a class="dropdown-item">Edit</a>
            <a class="dropdown-item">Delete</a>
        </div>
  </li>
  <li class="nav-item dropdown">
         <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Categories</a>
          <div class="dropdown-menu">
            <a class="dropdown-item">Edit</a>
            <a class="dropdown-item">Delete</a>
        </div>
  </li>
  </ul>
<ul class="navbar-nav ml-auto">
  <li class="nav-item dropdown">
    <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
      User
    </a>
    <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
      <a class="dropdown-item" href="#">Manage</a>
    </div>
  </li>
    </ul>

<link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-giJF6kkoqNQ00vy+HMDP7azOuL0xtbfIcaT9wjKHr8RbDVddVHyTfAAsrekwKmP1" crossorigin="anonymous">
    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.bundle.min.js" integrity="sha384-ygbV9kiqUc6oa4msXn9868pTtWMgiQaeYH7/t7LECLbyPA2x65Kgf80OJFdroafW" crossorigin="anonymous"></script>

<nav class="navbar navbar-expand-lg navbar-light bg-light"role="navigation">
     <a class="navbar-brand" href="#"role="navigation">Navbar</a>
    <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
<div class="collapse navbar-collapse" id="navbarSupportedContent">
<ul class="navbar-nav">
<li class="nav-item active">
  <a class="nav-link" href="index.html">Home <span class="sr-only">(current)</span></a>
  </li>
  <li class="nav-item dropdown">
         <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Links</a>
          <div class="dropdown-menu">
            <a class="dropdown-item">Edit</a>
            <a class="dropdown-item">Delete</a>
        </div>
  </li>
  <li class="nav-item dropdown">
         <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Categories</a>
          <div class="dropdown-menu">
            <a class="dropdown-item">Edit</a>
            <a class="dropdown-item">Delete</a>
        </div>
  </li>
  </ul>
<ul class="navbar-nav ml-auto">
  <li class="nav-item dropdown">
    <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
      User
    </a>
    <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
      <a class="dropdown-item" href="#">Manage</a>
    </div>
  </li>
    </ul>

It’s been a hot minute since I’ve used Bootstrap and am trying to get my NavBar to toggle the dropdown. I’ve looked at all bootstrap documentation and other forums on here. Is there something I’m missing?

<nav class="navbar navbar-expand-lg navbar-light bg-light">
     <a class="navbar-brand" href="#">Navbar</a>
      <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarNav">
<ul class="navbar-nav">
<li class="nav-item active">
  <a class="nav-link" href="index.html">Home <span class="sr-only">(current)</span></a>
  </li>
  <li class="nav-item dropdown">
         <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Links</a>
          <div class="dropdown-menu">
            <a class="dropdown-item">Edit</a>
            <a class="dropdown-item">Delete</a>
        </div>
  </li>
  <li class="nav-item dropdown">
         <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Categories</a>
          <div class="dropdown-menu">
            <a class="dropdown-item">Edit</a>
            <a class="dropdown-item">Delete</a>
        </div>
  </li>
  </ul>
<ul class="navbar-nav ml-auto">
  <li class="nav-item dropdown">
    <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
      User
    </a>
    <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
      <a class="dropdown-item" href="#">Manage</a>
    </div>
  </li>
    </ul>