Can't login to Admin console

Brand new install of 3.9.3 for Windows, after entering an admin username and password in the wizard, the setup completes, and the application launches. It presents a screen to log in to the Admin console, and when I enter the username and password I just set I get an error message that says the login is incorrect. I am quite certain the password is entered correctly. I have uninstalled and reinstalled several times, deleted the program directory in between, even tried entering different credentials, and cannot get past this login error. What am I doing wrong?

It doesn’t ask for admin’s username in the setup (asks for email). Username is always ‘admin’ (without the quotes).

That did it, I knew it had to be something simple.