Django rest framework api end points not accessble after implementing ouath 2 toolkit

Question

My django rest api endpoints were working with the JWT authentication. Later I changed that to Oauth 2 toolkit. All are working fine from postman rest app. But the api doc test endpoints are not working. It shows the following screen.

This page still shows even if I am logged in as administrator. Is there any change I need to do in the settings file?

Current settings in settings.py is

OAUTH2_PROVIDER = {
'SCOPES': {'read': 'Read scope', 'write': 'Write scope', 'groups': 'Access to your groups'}
}

REST_FRAMEWORK = {
'DATETIME_FORMAT': "%m/%d/%Y %H:%M:%S",
'DATE_FORMAT' : "%m/%d/%Y",
'DEFAULT_PERMISSION_CLASSES': (
    'rest_framework.permissions.IsAuthenticated',
),
'DEFAULT_AUTHENTICATION_CLASSES': (
    'oauth2_provider.ext.rest_framework.OAuth2Authentication',
),
'DEFAULT_PAGINATION_CLASS': 'rest_framework.pagination.LimitOffsetPagination',
'PAGE_SIZE': 50,
'EXCEPTION_HANDLER': 'app_utils.views.exception_handler'
}