Hi - this is Chuck :)
First you can never use runserver on PythonAnywhere. My instructions at https://dj4e.com/assn/dj4e_install.md say:
Just as a note, you never run the runserver command on PythonAnywhere. This functionality is replaced by the "reload" button on your Web tab. So if you are reading any Django instructions that say to do a runserver, instead do a check and then reload the application in the Pythonanywhere web UI.
Also you will never use localhost - in order to test, you need to connect to the web server at the URL that is shown under the Web tab in your PythonAnywhere user interface.
What it looks like you are doing is getting the password set on your PythonAnywhere site using changepassword - but then trying to log into my PythonAnywhere site at http://djtutorial.dj4e.com/admin using your password - which won't work.
Please read the instructions in the assignment carefully. Once you understand the differences between running Django locally and on PythonAnywhere in this first assignment, it will be second nature in later assignments.