You can reset your password on the login screen. Click on the Forgot your password? link.
Then enter the email address that you use to log into your Wahoo account.
You will get confirmation that the email was sent. If you don't receive this confirmation, check that your email address is entered correctly and that it matches what you use for your Wahoo account.
An email link will be sent to you. Click on it to be redirected to the Wahoo website. Once your password has been reset, you can log into your app using the same email address and the new password. Your new password will need to be at least 8 characters in length.