Issue with django administration

Hi everyone, i’m facing issue with freshly installed Sentry.
Once i’m logged in Admin console i’m trying to add a new user and getting this error message. ( Oops! Something went wrong
It looks like you’ve hit an issue in our server API. Don’t worry though! We use Sentry to monitor Sentry and it’s likely we’re already looking into this!)

Docker logs of “Web” container showing : file “/usr/local/lib/python3.8/site-packages/sentry/”, line 223, in get_form
{“form”: self.add_form, “fields”: admin.util.flatten_fieldsets(self.add_fieldsets)}
AttributeError: module ‘django.contrib.admin’ has no attribute ‘util’
06:46:09 [ERROR] django.request: Internal Server Error: /admin/sentry/user/add/ (status_code=500 request=<WSGIRequest: GET ‘/admin/sentry/user/add/’>)

Please help me to resolve this issue because i’m not able to add any user.