We use Google Accounts for authentication, so the email address you use to sign in to RK9.gg needs to be a primary Google Account email (not an email used as an alternate or recovery email for a Google Account). We believe Google has best-in-class account security features, and so we rely on them to vouch for who you are (authentication), and then we allow you to access certain things (authorization).
If you would like to use an existing email address that is not connected to a Google Account, this article has instructions on how to connect it. Once it has been connected to a Google Account, Google will be able to identify you for authentication purposes.
Please note this email must be the main Google Account email. It cannot be an alternate or alias email, nor a recovery email listed in a Google Account. You can verify the email addresses associated with your Google Account, and their roles, by going to your Google Account Profile - Personal info - Contact info Emails. We use the Google Account email, shown at the very top, for authentication.
To verify which email address Google is reflecting back to us for authentication purposes, go to your RK9 Profile by clicking on your name/email address shown in the upper right corner, and view the Google Account primary email listed under Account Details.