Arris: Cable internet

the Arris dg1670 is your modem , the actiontec wcb3000n is a Wireless Network Extender , the arris should be the only one getting the internet signal from your isp , if the actiontec wcb3000n is also hooked to coax cable , its probably using a Moca connection
instead of Ethernet ....you could try plugging your xbox into the Arris instead of the Actiontec but the Arris gateways like you have from brighthouse have been the absolute worst ones to go down for some reason...if you plug into the arris and its still
a no go , I would call your isp and see if they will replace it , they should be aware of the issue...

Try this:

Room with cable modem

coax cable from wall to coax input on moca

coax cable from coax output of moca to coax input of Arris

ethernet cable from LAN port of Arris to ethernet port of moca

Room with Xbox

coax cable from wall to coax input on moca

cap and do not use coax output of moca

ethernet cable from port on Xbox to port on moca

Power cycle your Arris.

Arris CM820A cable modem

Asus RT-AC68U router

Time Warner Cable

Arris TG862

Don't know about Firmware

Jayson, the Arris TM802G is a Cable Modem only, it does not have any sort of wireless / routing capability. This means that you have a router in your household that's giving other wireless devices in your household internet access.

Please reply with the Router's make and model number.

Thanks.