The best way to reset the password id through resetting the device itself. Locate the reset button. Press and hold it for a few seconds. The router will now automatically reboot. After that follow the steps to reset Arris router password.
Steps to reset password:
Type 192.168.0.1 in the URL section. This will direct you to the log in page.
Enter the default credentials.
Click on manage Wi-Fi network.
There you will the option of password.
Type a new password. Re enter to confirm it.
Log in through the new password to save and apply the changes.
Read more: update arris surfboard firmware