根据我的经验，当我尝试执行 runserver 但未在setting.py中安装所有自定义的 MIDDLEWARE 时，会发生这种情况。确定并安装中间件后，错误得以解决。

From my experience this happens when I try to execute runserver but I haven't installed all custom MIDDLEWARE in setting.py. After identifying and installing the middlewares the error is resolved.