问PHP上传14 PHP文件失败

EN

<form role="form" action="api/upload.php" method="post" enctype="multipart/form-data">
  <input id="file" name="file" type="file" />
  <input class="btn btn-primary" type="submit" value="Upload" />
</form>

<?php
if(isset($_FILES['file'])){
  $file = $_FILES['file'];
  $target_file = basename($_FILES["file"]["name"]);

  $file_name = $file['name'];
  $file_tmp = $file['tmp_name'];
  $file_size = $file['size'];
  $file_error = $file['error'];

  $file_ext = explode('.',$file_name);
  $file_ext = strtolower(end($file_ext));

  $allowed = array('txt', 'jpg', 'xlsx', 'pptx', 'docx', 'doc', 'xls', 'pdf');

  if(in_array($file_ext, $allowed)){
    if($file_error === 0){
      if($file_size <= 99600000){ // this was set to 600000
        $file_name_new = uniqid('', true) . '.' . $file_ext;
        $file_destination = '../files/' . $file_name;

        if(move_uploaded_file($file_tmp, $file_destination)){
          header("Location: ../index.php");
          die();
        }
        else{
          echo "There was a problem uploading the file";
        }
      }
      else{
        echo "The file is too large";
      }
    }
    else{
      echo "There was an error uploading the file";
    }
  }
  else{
    echo "The file type is not allowed";
  }
}
?>