So this would suggest your credentials are wrong, just like the error message says.
You might want to simply delete your ~/.n8n folder if you don’t have any production data in n8n yet (as per this topic you’ve opened) and also clean the database you’re currently using, seeing you are using Postgres here rather than the SQLite database from your other thread. This would give you a fresh start.
Depending on which Windows version your are using and how your system is set up the ~/.n8n folder might live inside your WSL filesystem.
Alternatively you could use the CLI command to reset your credentials but this would have to be executed inside your docker container as documented here.
Going forward if you’re using n8n locally and are the only one using it you might want to skip setting a username & password, especially if you run several n8n instances using different databases rather then setting different credentials.