What device do you have? 

What ip address are you using? 

if its a modem, did you try 192.168.100.1?

Arris  , 192.168.0.1 yes I did. No luck 

I tried it with modem hooked up to internet and unhooked as well. Now a message appears saying unsupported protocol.

try a Hard wire connection to the modem, mine responds to 10.0.0.1

I am having the exact same issue. Prior to doing a reset, my router had “unknown” clients showing and my settings were screwed up. It took several attempts for the reset to hold, using the 30-30-30 method, but now my configuration is showing a router IP address other than 192.168.0.1. It is showing 104.173.64.1 instead.

This address just worked for me. 

http://192.168.100.1:8080/

@gcman1016 when you responded you put you used 192.168.0.1. 

Make sure its 192.168.100.1