You tried to log into the admin portal with the wrong password. 

1. did you set it up with the app? or through the browser?
2. did someone else set it up for you`
3. if you don’t know the log in info to the browser portal, you might have to factory reset and start over from factory to login

There are two ways to change the Wi-Fi name and password for the SBG10.

The first option is through the SURFboard Central app. By setting up the app, you can easily change the Wi-Fi name and password.

Please find the link below, where you can follow the steps to set up the SURFboard Central app and update the Wi-Fi name and password.

http://arris.force.com/consumers/articles/General_FAQs/SURFboard-Central-Wi-Fi-Cable-Modem-Setup

http://arris.force.com/consumers/articles/General_FAQs/SURFboard-Central-Changing-the-Wi-Fi-Name-Password

The other option is through the web-based interface (GUI), where you can also change the Wi-Fi name and password.

Since you are locked out of the interface page, please restart the modem and try using the login credentials provided in the link below.

http://arris.force.com/consumers/articles/General_FAQs/SBG10-Web-Manager-Access

After logging in, you will be directed to the basic setup page, where you can change the Wi-Fi name and password directly on the front page.

If needed, for your reference please go to this link for detailed steps on how to update the Wi-Fi credentials.

http://arris.force.com/consumers/articles/General_FAQs/SBG10-Changing-the-Default-Wi-Fi-Name-Password