Bootstrap Toggle Burger Menu not working when switched to mobile view

<nav class="navbar navbar-expand-lg navbar-dark  px-2 " style="background-color:#E53935;">
          <a class="navbar-brand" href="#">HeadOverMeals</a>
          <button class="navbar-toggler" type="button" data-toggle="collapse" data-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="#">Home</a>
              </li>
              <li class="nav-item active">
                <a class="nav-link" href="#">Contact</a>
              </li>
              <li class="nav-item active">
                <a class="nav-link" href="#">Cart</a>
              </li>
            </ul>
          </div>
        </nav>