AttributeError at /admin/login/ 'MetaDict' object has no attribute 'pk'

[xycfree]

Request Method:	POST
http://127.0.0.1:8007/admin/login/?next=/admin/
1.9
AttributeError
'MetaDict' object has no attribute 'pk'
D:\tools\python36\venv2\lib\site-packages\django\contrib\auth_init_.py in login, line 111
D:\tools\python36\venv2\Scripts\python3.6.exe
3.6.5

[xycfree]

[29/Aug/2018 19:32:28] "POST /api/auth/ HTTP/1.1" 200 6639 [29/Aug/2018 19:34:20] "GET /admin/ HTTP/1.1" 302 0 [29/Aug/2018 19:34:20] "GET /admin/login/?next=/admin/ HTTP/1.1" 200 1679 Internal Server Error: /admin/login/ Traceback (most recent call last): File "D:\tools\python36\venv2\lib\site-packages\django\core\handlers\base.py", line 149, in get_response response = self.process_exception_by_middleware(e, request) File "D:\tools\python36\venv2\lib\site-packages\django\core\handlers\base.py", line 147, in get_response response = wrapped_callback(request, *callback_args, **callback_kwargs) File "D:\tools\python36\venv2\lib\site-packages\django\views\decorators\cache.py", line 57, in _wrapped_view_func response = view_func(request, *args, **kwargs) File "D:\tools\python36\venv2\lib\site-packages\django\contrib\admin\sites.py", line 407, in login return login(request, **defaults) File "D:\tools\python36\venv2\lib\site-packages\django\contrib\auth\views.py", line 49, in inner return func(*args, **kwargs) File "D:\tools\python36\venv2\lib\site-packages\django\views\decorators\debug.py", line 76, in sensitive_post_parameters_wrapper return view(request, *args, **kwargs) File "D:\tools\python36\venv2\lib\site-packages\django\utils\decorators.py", line 149, in _wrapped_view response = view_func(request, *args, **kwargs) File "D:\tools\python36\venv2\lib\site-packages\django\views\decorators\cache.py", line 57, in wrapped_view_func response = view_func(request, *args, **kwargs) File "D:\tools\python36\venv2\lib\site-packages\django\contrib\auth\views.py", line 76, in login auth_login(request, form.get_user()) File "D:\tools\python36\venv2\lib\site-packages\django\contrib\auth_init.py", line 111, in login request.session[SESSION_KEY] = user._meta.pk.value_to_string(user) AttributeError: 'MetaDict' object has no attribute 'pk' [29/Aug/2018 19:34:31] "POST /admin/login/?next=/admin/ HTTP/1.1" 500 104218