Cox Not Allowing 3rd Modem to Connect?

First off, thank you for the response.

Secondly, here are the signal levels. https://imgur.com/a/DyC4fyV

https://imgur.com/a/DyC4fyV

The model router I have is a TP-Link AX1800 (edited)

I forgot to check the WAN IP, so I'll do that and check back in a moment.

Interesting. Looks like your modem is online and passing all checks. What model router do you have? SB6190 is your stand alone modem. I assume you are using something for multiple computers and Wi-Fi? My guess is this is some kind of provisioning issue.

Oh, I don't know why I read that as modem! My router is a TP-Link AX1800. Sorry about that!

Probably saw model as modem. I say model because some people just give the manufacture.

Luckily TP-Link has a very good support site. First, log in by going to 192.168.0.1 in a browser. Then click on Advanced > Status > Internet which should look something like this. Are you seeing a IP there? What is the first number of that IP? 172.x.x.x?

Complete stab in the dark here...but do you think OP is daisy-chaining the Arris off the Panoramic?  My old browser doesn't like Imgur.  I didn't understand "3rd Modem" in the title of this post.

No, the tech left the Panoramic with me. Yes, I have tried resetting multiple times, just keeps coming back with an error.

Is the Panoramic connected?  Where is your Arris?

If the tech left the Panoramic with you, why'd the tech recommend a modem?  The Panoramic is a combo modem-router.

You can't add or change your modem via the webpage.  This link is only to upgrade your plan.  It's a sales pitch.  The link beneath it, however, would allow you to reset this device.

After clicking Reset on your account...with your Arris connected...does your Arris reboot?

He left me with the Pano because the other modem I have (the Netgear) was not working and I did not have the Arris at the time. The Pano allowed me to get hooked up to the internet in the meantime. I bought the Arris and have been trying to connect it since. Whenever the Pano is connected, everything works fine, I connect the Arris and everything bjorks out despite all readings supposedly being good. For whatever reason, Cox's connection is just not getting through to the modem, despite my wifi router having all green showing it is connected and reading the modem's signals.

I connect the Arris

I'm not insulting your intelligence...but to what are you connecting the Arris?

System won't allow multiple occurrences unless they are paying for them. You can have 2 modems provisioned for data, IF, you are paying for 2 instances of internet service. I ran into that quite often, but if they are ONLY paying for 1 instance of Internet service, the system will not allow  more than the single D1 occurrence. 

::edit:: I see what your saying. You mean the system won't even allow for a D2 occurrence unless there is data service already assigned to D2?

To re-provision, Cox will remove Internet service from your account.  It'd be like if I called Cox to cancel my Internet service.  No Internet equipment would then be provisioned on my account.  All gone Internet.

After the service is removed, Cox will re-add the occurrence (D (Data)) for Internet service and whatever modem is connected, it will be configured for your service.

What do you think was the reason Cox said the SB6190 was already provisioned? Rep. error?

"Provision" has nothing to do with hardware.  Your account can be provisioned for Internet, cable-TV and telephone with no equipment actually connected to the coaxial or fiber in your house.  Think if you ordered service at the Solution Store and drove home with equipment.  Your account is established and provisioned with three services...but nothing is connected.

Once you get home and start connecting stuff, Cox will authenticate, authorize and configure your equipment for your services.

When you troubleshoot and nothing has worked, Cox can "re-provision" your service to perhaps wipe out a glitch in their system, which may have been causing your errors.