navbar doesn't expand on mobile with bootstrap5

Question

I'm making a website with Bootstrap 5 and my navbar doesn't work. When I'm on mobile it does not expand.

@import url('https://fonts.googleapis.com/css2?family=Poppins:ital,wght@0,100;0,200;0,300;0,400;0,500;0,600;0,700;0,800;0,900;1,100;1,200;1,300;1,400;1,500;1,600;1,700;1,800;1,900&display=swap');
/*
#FF3633 - Vermelho

*/
*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', sans-serif;
}
/* estilo - header */
.navbar {
    background-color: #131313;
    padding: 1rem 8rem;
    z-index: 1000;

}

.navbar .navbar-brand {

    font-size: 1.4rem;
    font-weight: 800;
}

#navbarSupportedContent > ul > li:nth-child(n) > a {
  color: #fff;
  font-size: 1.1rem;
  padding: 0 0.8rem;
}

#navbarSupportedContent > ul > li:nth-child(n) > a:hover {
    color: #FF3633;
}

#navbarSupportedContent button {
    background-color: #FF3633;
    font-weight: 600;
    padding: 0.4rem 1.4rem;
    border-radius: 30px;
    outline: none;
}

#navbarSupportedContent button:hover {
    background-color: #CC3036;
}

<header>
<nav class="navbar navbar-expand-lg navbar-dark fixed-top">
    <div class="container-fluid">
      <a class="navbar-brand" href="#">
        <img src="img/logo-wt.png" width="100" height="30" alt="">
      </a>
      <button class="navbar-toggler" type="button" data-bs-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 mx-auto mb-2 mb-lg-0">
          <li class="nav-item">
            <a class="nav-link" href="#">Quem Somos</a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">Serviços</a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">Serviços</a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">Contato</a>
          </li>

        </ul>
          <button class="btn text-light" type="submit">Contato</button>
        </div>
    </div>

</nav>
<div class="mid">
    <video autoplay muted loop>
        <source class="embed-responsive" src="darkvd.mp4" type="video/mp4">
    </video>
    <div class="hero text-center">
        <h2 class="text-light display-3 fw-bold m-lg-3 mx-3">Suporte Linux e Cloud</h2>
        <p class="text-light mx-auto">Criando um paralelo entre baixo custo, disponibilidade, praticidade e satisfação</p>
        <a class="text-light fw-bold m-lg-3 mx-3 " href="#"> SAIBA MAIS </a> 

    </div>
</div>
<header>
<nav class="navbar navbar-expand-lg navbar-dark fixed-top">
    <div class="container-fluid">
      <a class="navbar-brand" href="#">
        <img src="img/logo-wt.png" width="100" height="30" alt="">
      </a>
      <button class="navbar-toggler" type="button" data-bs-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 mx-auto mb-2 mb-lg-0">
          <li class="nav-item">
            <a class="nav-link" href="#">Quem Somos</a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">Serviços</a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">Serviços</a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">Contato</a>
          </li>

        </ul>
          <button class="btn text-light" type="submit">Contato</button>
        </div>
    </div>

</nav>
<div class="mid">
    <video autoplay muted loop>
        <source class="embed-responsive" src="darkvd.mp4" type="video/mp4">
    </video>
    <div class="hero text-center">
        <h2 class="text-light display-3 fw-bold m-lg-3 mx-3">Suporte Linux e Cloud</h2>
        <p class="text-light mx-auto">Criando um paralelo entre baixo custo, disponibilidade, praticidade e satisfação</p>
        <a class="text-light fw-bold m-lg-3 mx-3 " href="#"> SAIBA MAIS </a> 

    </div>
</div>

button pic

Answer 1

Bootstrap 5 has namespaced all of the data attribute names with data-bs-*.
Change the following:

data-target="#navbarSupportedContent"

to this:

data-bs-target="#navbarSupportedContent"