I guess you would have created this user through other means and not python manage.py createsuperuser

This happens when you have two authentication systems. ie.,. you might have django inbuilt authentication and (for example) DRF token based authentication.

To login to the backend(django admin) you will have to use python manage.py createsuperuser

To change the pwd, use the below,

python manage.py changepassword 

I guess you would have created this user through other ways and not python manage.py createsuperuser

This happens when you have two authentication systems. ie.,. you might have django inbuilt authentication and (for example) DRF token based authentication.

To login to the backend(django admin) you will have to use python manage.py createsuperuser

To change the pwd, use the below,

python manage.py changepassword