When you signed up for MyPrize, you either created an account manually or you signed up with Google. For all subsequent logins, you will need to use the same method as when you signed up.
If you signed up with Google, you will need to log in with Google.
If you signed up manually, you will need to log in with the email and password you created.
This means that if you signed up with one method and attempt to log in with the other, you will receive an error message and not be able to log in. Please try again with your original login method and you should be able to log in successfully.