In the case that you've forgotten your password or need to reset it for another reason, simply navigate to the request password reset page: https://beta.mindjoy.com/request_password_reset
You should see a page that looks like this. Enter the email address that you used to sign up to Mindjoy, and then check your inbox for instructions on how to reset your password.
Note: make sure to check your spam or alternative inboxes in case it ended up in the wrong spot!