Hi -midnight,
Throw that Arris router out onto the lawn, it is a garbage product, and let your dog go and play with it.
With Arris you have a backdoor in the backdoor.
What if the port is secure and they come and enter your house through the balcony?
You sure need that avator dog then to grow a bit nastier to keep hackers out.
Read about why Arris is not the wifi router you should use:
https://w00tsec.blogspot.nl/2015/11/arris-cable-modem-has-backdoor-in.html That was then in 2015 and they haven't produced them very more secure since!
The only sensible thing you did is go against the advice to set a password as
ARRIS password of the day is a remote backdoor known since 2009. So you unwillingly know more about security than others are willing to admit,
polonus (volunteer website security analyst and website error-hunter)