If you changed the settings and credentials but do not seem to remember them. Here are the steps on how to reset Arris router to factory default. Let’s take a look at the steps.
 Turn the router off.
 Press and hold the WPS button on the router.
 Switch on the router back.
 Power light on the router should be on.
 Now, release the WPS button.
 The router will reboot automatically.
You can log in through the default username and password.