To check and to isolate the issue can you please try on direct connection without coax cable. Disconnect the coax cable from the modem then try accessing modem GUI using chrome or any web browser and use the following instruction to login.

http://arris.force.com/consumers/articles/General_FAQs/SB8200-Web-Manager-Access

I tried as instructed and got nowhere.

What I do not know is what the firmware version is and I may try calling Cox to see if they can tell me. but I don’t get either the admin login or the Connection page

“The admin login is not available on firmware version prior to 1.01.009.47 and the Connection page will appear” 

Here is what I get no matter what WITH cable

“This site can’t be reached

192.168.100.1 took too long to respond.

Try:

• Checking the connection
• Checking the proxy and the firewall
• Running Windows Network Diagnostics

ERR_CONNECTION_TIMED_OUT”

What I get without cable is the same except the error is different.

I can’t disconnect cable as Wife is using her computer now.

I’ve tried using Edge, Bing, Chrome & Safari,

no dice.

If you tried all the possible troubleshooting steps and still you are unable to access the web portal, I would suggest to factory reset the modem.

http://arris.force.com/consumers/articles/General_FAQs/SB8200-Factory-Reset

Also, please make sure that there is no VPN enabled on the device which you are trying to access the webportal.

I would suggest accessing the web portal without co-axial cable. If you are unable to access it, then please perform factory reset and try again.

I have tried a factory reset multiple times (paperclip pressing switch in reset hole for 10 seconds), with or without the coax cable to no avail.

The best I ever got was a small box with places for username and password,

I tried username as ‘admin’ and password as ‘password’ or last 8 of serial number, to no avail.

Below has the IPv6 and machine address removed from the list by me for security reasons.

Link speed (Receive/Transmit):    1000/1000 (Mbps)
IPv4 address:    192.168.1.2
IPv4 DNS servers:    192.168.1.1 (Unencrypted)
Manufacturer:    Killer
Description:    Killer E2600 Gigabit Ethernet Controller
Driver version:    1168.5.112.2022

At this point, unless the Manager could be of use to me or for some diagnostic purpose, I may drop the subject because I’ve spent hours searching for a way to acquire it and keep being given the same advice and keep having the same result.

If you tried all the possible troubleshooting steps and unable to access the web portal.

I would suggest visiting www.arris.com/consumersupport for further assistance.