Default credentials for ARRIS TG1682P

I have an ARRIS TG1682P modem provided by Xfinity.

I would like to update the password from the factory settings and create another access point. Support told me that I own this modem and that they do not have access to it.

I accessed the modem via https://10.0.0.1 and tried typical login combinations like "admin-password" or "admin-admin," but neither worked. There is no login password information on the router body.

I reset the modem using the button on the back, but nothing changed. Even the Wi-Fi settings are still the same.

Does anyone know the default credentials for an ARRIS TG1682P modem?