I couldn't log in no matter how many times I tried using PythonAnywhere's admin login form.
It was caused by me trying to enter with a PythonAnywhere account.
If you have experience building django in your local environment, I think you already know.
I completely forgot that I need to create a superuser.
[Superuser] How to create a superuser in PythonAnywhere's console.
As a superuser in the console, you will need to enter your name, email address, and password.
python manage.py createsuperuser
I was able to log in when I challenged the form again with the superuser created here.
Please try to reference.