请教一个 Flask 中模态框中提交表单的问题

我在模态框中设置了一个表单，使用 POST 提交，遇到的问题是提交后收不到表单数据，第一次在模态框中写表单，求教是哪里的问题。

模态框代码:

    <!-- 模态框（ Modal ） -->
    <form action="{{ url_for('dashboard.freeze_user') }}" method="POST">
    <div class="modal fade" id="freeze_users" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
      <div class="modal-dialog">
          <div class="modal-content">
              <div class="modal-header">
                  <h4 class="modal-title -align-center" id="myModalLabel">确定冻结该账户？</h4>
                  </div>
                  <div class="modal-body">

                    <input type="username" name="user" id="user" value="" disabled="disabled">
                    <input type="submit" class="btn btn-danger" value="确认">
                    <button type="button" class="btn btn-dark" data-dismiss="modal">关闭</button>

                  </div>
          </div><!-- /.modal-content -->
      </div><!-- /.modal -->
    </div>
    </form>

后端代码：

@dashboard_bp.route('/api/users/freeze', methods=['POST'])
@admins_only
def freeze_user():
    user = request.form.get("user")
    print(request.data)
    print(user)
    # if user:
    #     print(user)
    return redirect(url_for('dashboard.users_info'))

打印信息：

127.0.0.1 - - [03/May/2020 19:29:34] "GET /usersinfo HTTP/1.1" 200 -
127.0.0.1 - - [03/May/2020 19:29:38] "POST /api/users/freeze HTTP/1.1" 302 -
b''
None
127.0.0.1 - - [03/May/2020 19:29:38] "GET /usersinfo HTTP/1.1" 200 -