Метод проверки подлинности ModelBackend делает это:
def authenticate(self, request, username=None, password=None, **kwargs):
if username is None:
username = kwargs.get(UserModel.USERNAME_FIELD)
try:
user = UserModel._default_manager.get_by_natural_key(username)
except UserModel.DoesNotExist:
# Run the default password hasher once to reduce the timing
# difference between an existing and a nonexistent user (#20760).
UserModel().set_password(password)
else:
if user.check_password(password) and self.user_can_authenticate(user):
return user
и user_can_authenticate
- это:
def user_can_authenticate(self, user):
"""
Reject users with is_active=False. Custom user models that don't have
that attribute are allowed.
"""
is_active = getattr(user, 'is_active', None)
return is_active or is_active is None
У вашего пользователя для is_active установлено значение True?