I cannot install WPMU DEV Dash via composer

I have a 30 day trial with smush pro. I tried to install the wpmu dev dashboard using composer following the instruction here https://premium.wpmudev.org/docs/getting-started/installing-wpmu-dev-plugins-via-composer/
I get to the part where it asks me for the username in the terminal, but after using my API key there it says invalid credentials.