Upload Button Not Clickable in Popup Form

I’m working on a web project where I have a popup form for uploading images and adding game names. Everything seems to be in place, but the upload button in the popup form isn’t clickable.

Does anyone have suggestions on why the button might not be clickable and how to resolve this issue?

document.getElementById('addMiniCardBtn').addEventListener('click', function() {
  showPopupForm();
});

document.querySelector('.close-btn').addEventListener('click', function() {
  hidePopupForm();
});

document.getElementById('uploadForm').addEventListener('submit', function(event) {
  event.preventDefault();

  var formData = new FormData(this);

  fetch('upload_card.php', {
      method: 'POST',
      body: formData
    })
    .then(response => response.json())
    .then(data => {
      if (data.success) {
        var card = data.card;
        var miniCardContainer = document.getElementById('miniCardContainer');
        var miniCard = document.createElement('div');
        miniCard.className = 'mini-card';
        miniCard.innerHTML = `
        <img src="${card.image_path}" alt="${card.game_name}">
        <div class="game-names">${card.game_name}</div>
        <img src="images/trashcan.png" class="delete-icon" alt="Delete" onclick="deleteMiniCard(this, '${card.id}')">
      `;
        miniCardContainer.appendChild(miniCard);
        hidePopupForm();
      } else {
        alert(data.message);
      }
    })
    .catch(error => {
      console.error('Error:', error);
    });
});
<div class="popup-form" id="popupForm">
  <div class="popup-content">
    <form id="uploadForm" action="upload_card.php" method="POST" enctype="multipart/form-data">
      <label for="file">Select Image:</label>
      <input type="file" id="gameImageFile" name="file" accept="image/*" required>
      <label for="gameName">Game Name:</label>
      <input type="text" id="gameName" name="gameName" required>
      <button type="submit" id="uploadButton">Upload</button>
      <button type="button" class="close-btn" onclick="hidePopupForm()">Close</button>
    </form>
  </div>
</div>