In case you've forgotten your password, you can always reset your password directly here: https://www.mentimeter.com/auth/reset_passwords. You can also change it directly in your Account settings.
If you have created a Mentimeter account previously by logging in via Google/Facebook, you can add a password if you do not wish to log in directly from there anymore. Simply go to the same password reset link above - it works even though you do not have a password at the moment.
After accessing the password reset link, you will get an email with a link where you can change or create a password so that you can log in with your email address.
Please reach out to us at hello@mentimeter.com if the password reset process didn't work out for you!