How to access Spectrum Analyzer

Cox doesn't block port 8080. 

https://www.cox.com/residential/support/internet-ports-blocked-or-restricted-by-cox.html

Also, your MB8600 isn't a Motorola modem, it's a ZOOM Modem. Zoom Telephonics leased, then purchased the Motorola NAME from Arris, who actually purchased Motorola and their intellectual property information. Arris produces the Surfboard line, originally produced by Motorola, and leased, then sold the NAME to Zoom. 

Zoom had this huge article in one of the major industry magazines boasting the fact that they can now use the name Motorola on their equipment and people would buy their equipment due to name recognition, which I find underhanded AND deceitful. People buy due to name recognition thinking they are getting a quality product, and they end up with trash I wouldn't PAY someone to use. 

Edit - BTW, port 80 INBOUND is blocked, that means from the internet to the WAN port. YOU are trying to access your device internally from the LAN port, and nothing that Cox blocks, is going to affect something taking place from the LAN side. Proof of that, disconnect your CABLE wire so that your modem cannot load Cox CFG file and go online, and then simply access it through your LAN port.