[Django]-Why getting django.core.exceptions.AppRegistryNotReady: Apps aren't loaded yet. while creating CustomUser and CustomUserManager

You need to set correct python path to your user model, but not reference the model class object it self. Django needs to initialise properly first.
change
AUTH_USER_MODEL = loginsignup.models.CustomUsers
to
AUTH_USER_MODEL = "loginsignup.models.CustomUsers"
and remove import loginsignup.models from settings.py